TW202506813A - Methods of modifying polycarbonates with siloxanes - Google Patents

Abstract

The present application discloses a method including contacting one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups with one or more reactive siloxane compounds terminated by one or more acetoxy, methoxy, ethoxy, halide, hydrogen atoms in a solvent system to form one or more siloxane modified polycarbonates in a recovery solution, and the one or more reactive polycarbonates comprise one or more waste polycarbonates.

Description

Method for modifying polycarbonate using siloxane

A method for chemically modifying recycled polycarbonate to obtain a polycarbonate having improved molecular weight, heat resistance and/or reduced hydroxyl and/or carboxyl groups in a polymer composition is disclosed.

Polycarbonate and copolymers containing carbonate units are used in a variety of molded structures. The molded structures can be used in a variety of applications, including housings for electronic components, automotive parts, medical devices, household appliances, speakers, home furnishings, and the like. Over time, polycarbonate and its copolymers degrade. Degraded polycarbonate tends to accumulate in waste materials. Because the degradation of polycarbonate and its copolymers introduces undesirable side effects, such as the introduction of undesirable derivative monomers and reduced properties due to molecular weight loss, steps need to be taken to absorb and recycle the polycarbonate.

Therefore, there is a need for technology to modify recycled polycarbonate so that the polycarbonate has properties that can be used in new consumer products.

The present application discloses a method, which includes contacting one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups with one or more reactive siloxane compounds terminated with one or more acetyloxy, methoxy, ethoxy, halogenide or hydrogen atoms in a solvent system to form one or more siloxane-modified polycarbonates in a recovery solution, wherein the one or more reactive polycarbonates include one or more waste polycarbonates.

The one or more reactive polycarbonates may include the one or more waste polycarbonates in an amount of about 5 weight percent to about 95 weight percent based on the total amount of the reactive polycarbonate. The free hydroxyl groups and/or carboxyl groups may be located at one or more ends of the reactive polycarbonate. The free hydroxyl groups and/or carboxyl groups may be located along the main chain of the reactive polycarbonate. The siloxane-modified polycarbonates may have a number and/or weight average molecular weight greater than at least 5 percent of the number and/or weight average molecular weight of the reactive polycarbonates incorporated into the siloxane-modified polycarbonate. The method may further include contacting the solvent system and one or more waste feedstocks including the one or more waste polycarbonates and one or more non-polycarbonate compounds to form the recovery solution; and separating at least some of the one or more non-polycarbonate compounds from the recovery solution. The method may further include contacting one or more precursor siloxane compounds with water to form the one or more reactive siloxane compounds in the recovery solution; and contacting the recovery solution with one or more polycarbonate solvents to form the solvent system including the water and the one or more polycarbonate solvents in the recovery solution. The method may further include contacting the one or more reactive polycarbonates with one or more allyl halides to form one or more vinyl ether terminated polycarbonates configured to react with the hydrogen atoms of the one or more reactive siloxane compounds and form the one or more siloxane modified polycarbonates. The one or more allyl halides may be terminated by an olefin and a halide and contain between one and one hundred carbon atoms between the halide and the carbon at the olefin. The method may include contacting one or more scavengers with the recovery solution to scavenge the acid formed by contacting the one or more reactive polycarbonates and the one or more reactive siloxane compounds. The reactive polycarbonate and the reactive siloxane compound may be contacted in the presence of a catalyst configured to promote the formation of the siloxane-modified polycarbonate. The solvent system may include at least a polycarbonate solvent configured to dissolve the one or more reactive polycarbonates, and may further include water as appropriate. The one or more reactive siloxane compounds may include between one and one hundred siloxane units linked into chains terminated by at least one hydrogen, acetyloxy, methoxy, ethoxy, halide group, or any combination thereof.

The present disclosure provides a polymerizable composition comprising one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups along the backbone of the one or more reactive polycarbonates and/or at one or more ends of the one or more reactive polycarbonates, wherein the one or more reactive polycarbonates comprise one or more waste polycarbonates. The polymerizable composition comprises a solvent system comprising one or more polycarbonate solvents and/or water. The polymerizable composition includes: one or more siloxane modifiers including at least one of the following: one or more reactive siloxane compounds terminated by at least one hydrogen and one or more allyl halides; one or more reactive siloxane compounds terminated by at least one acetyloxy, methoxy, ethoxy, halide, or any combination thereof; or one or more precursor siloxane compounds configured to form in water the reactive siloxane compounds terminated by at least one halide. The one or more reactive polycarbonates and the siloxane modifiers are capable of reacting in the solvent system to form one or more siloxane-modified polycarbonates.

The present disclosure provides a polymer composition comprising one or more siloxane-modified polycarbonates. The siloxane-modified polycarbonates include one or more polycarbonate segments, one or more siloxane segments, and the one or more siloxane segments are connected to the one or more polycarbonate segments at oxygen atoms along the main chain of the one or more polycarbonate segments and at the ends of the one or more polycarbonate segments. At least some of the one or more siloxane segments connect two or more polycarbonate segments.

The one or more polycarbonate segments may include at least about 5 to 100 weight percent or more of dead polycarbonate residues based on the total amount of the siloxane-modified polycarbonate. Each of the one or more siloxane segments may contain between two and one hundred siloxane repeating units. The polymer composition may be substantially free of hydroxyl and/or carboxyl-containing compounds.

The present technology allows reactive polycarbonates to be modified by reactive siloxane compounds to form siloxane-modified polycarbonates having properties such as improved molecular weight, heat resistance and/or reduced hydroxyl and/or carboxyl groups in the polymer composition. Reactive siloxane compounds are advantageous in recycling solutions containing recycled polycarbonate because the formation and use of such reactive siloxane compounds may be directly in the recycling solution so that the reactive siloxane compound can be formed and the recycled polycarbonate can be repaired in the same step. The addition of reactive siloxane compounds can be used to modify the properties of reactive polycarbonates and optionally remove smaller hydroxyl-containing compounds such as bisphenol A.

The present technology allows the reactive groups of reactive polycarbonates to be modified to form siloxane-modified polycarbonates having flame retardancy, improved molecular weight and/or other improved polymeric properties. The reactive siloxane compounds provide dual benefits or remove hydroxyl and/or carboxyl groups on the reactive polycarbonate and improve the polymeric properties of the waste polycarbonate by reacting the reactive siloxane compounds with one or more carboxyl and/or hydroxyl groups.

Siloxane-modified polycarbonate refers to a polycarbonate including a residual group of a reactive siloxane compound. The reactive polycarbonate includes at least one reactive group as described herein. The siloxane-modified polycarbonate or reactive polycarbonate may be composed of original polycarbonate, waste polycarbonate, or any combination thereof. The siloxane-modified polycarbonate as described herein includes at least a residual group of a reactive siloxane compound and a reactive polycarbonate. The term repaired refers to adjusting the molecular weight of the waste polycarbonate or reactive polycarbonate to a siloxane-modified polycarbonate having a different molecular weight or a reduced number of carboxyl and/or hydroxyl end groups. The recovery solution includes at least a solvent system and at least one polycarbonate compound. The solvent system includes one or more solvents that are miscible or immiscible. Waste polycarbonate refers to polycarbonate in waste feedstock. Virgin polycarbonate refers to polycarbonate made by one or more techniques that react one or more diols and carbonic acid to form polycarbonate. As used herein, functional compounds terminate, extend or branch one or more polycarbonate chains and may or may not react with one or more reactive siloxane compounds.

The scrap material includes at least some scrap polycarbonate. The scrap material includes scrap polycarbonate and at least one other scrap non-polycarbonate compound, such as a metal compound. The scrap material contains about 10 weight percent to less than 100 weight percent of scrap polycarbonate. The non-polycarbonate compound includes one or more of metals, non-polycarbonate polymers, battery electrolytes, small organic compounds, oligomeric compounds, or any combination thereof. The non-polycarbonate compound may include one or more compounds that are typically mixed or blended with polycarbonate, including non-polycarbonate-containing polymers (such as styrenics, polystyrene, styrene acrylonitrile, acrylonitrile butadiene, butadiene elastomer, high impact polystyrene, polymethyl methacrylate), flame retardants, UV stabilizers, fillers, antioxidants, other additives, other polymers, or any other non-polycarbonate compounds. Examples of waste materials may include any non-polycarbonate materials in any waste containing polycarbonate, such as electronic components, plastic waste, toys, packaging, conveyors, trays, automotive parts, medical devices, home appliances, speakers, home decorations, casings of any other electronic devices including non-polycarbonate polymers, metals, printed circuit boards, batteries, magnets, or any combination thereof. A portion of the non-polycarbonate compounds in the waste materials may be removed by one or more pre-treatment steps prior to contacting the waste materials and the polycarbonate solvent so that some of the non-polycarbonate compounds are not undesirably dissolved in the polycarbonate solvent.

As used herein, one or more means that at least one or more of the listed components can be used as disclosed. As used herein, a alkyl group refers to a group containing one or more carbon atom backbones and hydrogen atoms, which may optionally contain one or more heteroatoms. In the case where the alkyl group contains heteroatoms, the heteroatoms may form one or more functional groups well known in the art. The alkyl group may contain cycloaliphatic segments, aliphatic segments, aromatic segments, or any combination of such segments. The aliphatic segments may be straight or branched. The aliphatic segments and cycloaliphatic segments may include one or more double bonds and/or triple bonds. Included alkyl groups are alkyl, alkenyl, alkynyl, aryl, cycloalkyl, cycloalkenyl, alkaryl, and aralkyl. Cycloaliphatic groups may contain both cyclic and non-cyclic moieties. Alkylene means a alkyl group or any of the subsets described, such as alkylene, alkenylene, alkynylene, arylene, cycloalkylene, cycloalkenylene, alkarylene, and aralkylene, having more than one valence. Valence as used herein means a covalent bond between an alkyl or alkylene group and another group, such as a group or atom containing a carbonyl, oxygen, nitrogen, or sulfur, or a basic compound as mentioned. Unless otherwise specified, as used herein, weight percentages or parts by weight refer to or are based on the weight of the composition. Tg is the temperature or temperature range at which a polymeric material exhibits a sudden change in its physical properties, including, for example, mechanical strength. Tg can be determined by differential scanning calorimetry (DSC). As used herein, post-industrial refers to a material source that is generated during the manufacture of a good or product. As used herein, post-consumer refers to a material source that is generated after the ultimate consumer has used the material in a consumer good or product.

As used herein, a hydroxyl and/or carboxyl-containing compound is meant to include at least one hydroxyl or carboxyl group bound to a carbon atom and having a molecular weight of about 500 g/mol or less, about 2000 g/mol or less, or about 3000 g/mol or less. The hydroxyl and/or carboxyl-containing compound may be a residue of a polycarbonate and have a molecular weight as described herein. As described herein, a polycarbonate oligomer may be distinguished from a hydroxyl and/or carboxyl-containing compound by having a number average or weight average molecular weight of 1000 g/mol or greater, 3000 g/mol or greater, or 5000 g/mol or greater. The hydroxyl and/or carboxyl-containing compound may include more than one repeating unit that is a residue of a polycarbonate or a derivative thereof. The repeating units containing hydroxyl and/or carboxyl compounds can be those repeating units described with respect to the polycarbonates discussed herein, the repeating units being terminated by at least one hydroxyl or carboxyl group. The hydroxyl and/or carboxyl compounds can include one or more bisphenol A compounds or derivatives thereof. The hydroxyl and/or carboxyl compounds can be separated from the recovery solution by any of the techniques described herein, such as by contacting a solvent with the recovery solution to extract the hydroxyl and/or carboxyl compounds, using an absorbent or adsorbent to remove the hydroxyl and/or carboxyl compounds, additives that precipitate the hydroxyl and/or carboxyl compounds, applying an electric charge to the compound to remove the hydroxyl and/or carboxyl compounds, filtering the hydroxyl and/or carboxyl compounds, or any other separation technique described herein. After one or more separation steps for removing hydroxyl and/or carboxyl compounds from the recovered solution, the polycarbonate solution can be substantially free of hydroxyl and/or carboxyl compounds. Substantially free of hydroxyl and/or carboxyl compounds can be about 150 ppm or less, about 100 ppm or less, or about 50 ppm or less of hydroxyl and/or carboxyl compounds. Substantially free of hydroxyl and/or carboxyl compounds can be about 25 ppm or less, 10 ppm or less, or an amount that is undetectable using known methods. Using functional compounds, reactive siloxane compounds, and/or precursor siloxane compounds, and/or separation techniques to remove hydroxyl and/or carboxyl groups can reduce the hydroxyl and/or carboxyl compounds in the recovered solution and/or polymeric composition described herein by a certain weight percentage. The hydroxyl and/or carboxyl compounds may be reduced by about 10 percent or more, about 30 percent or more, or about 50 percent or more. The hydroxyl and/or carboxyl compounds may be reduced by about 70 percent or more, about 90 percent or more, or about 95 percent or more. The hydroxyl and/or carboxyl compounds may be determined by any technique known to those skilled in the art. As an example, free phenolic substances (including bisphenol-a, phenol, and tertiary butylphenol) may be detected using HPLC equipped with a standard C18 column and a fluorescent detector with an excitation wavelength of 310 nm and emission monitoring at 275 nm. Quantification may be accomplished by using external standards of BPA and phenol. Sample preparation may include dissolving 1 g of PC sample in 5 mL of dichloromethane and then adding 20 mL of acetonitrile under continuous shaking. 2 mL of the supernatant was filtered through a 0.45 µm syringe filter and then analyzed by HPLC.

As used herein, polycarbonate means a polymer containing carbonate units. Such polymers may be homopolymers consisting essentially of carbonate monomer units or copolymers containing one or more other monomer units (co-monomer units) and carbonate units. Such copolymers may be block copolymers containing blocks of two or more different monomer units, or may be random copolymers in which different monomer units are randomly positioned along the polymer backbone. When required for the intended use, other monomer units may include any monomer units that do not negatively affect the inherent properties of polycarbonate (e.g., heat resistance, impact resistance, moldability, flexural modulus, flexural strength, haze, and transparency). Exemplary co-monomer units are ester units, polysiloxane units, and the like. As disclosed herein, the amount of the carbonate monomer unit in the copolycarbonate is selected so that the resulting polymer retains the desirable properties of polycarbonate. Copolycarbonate can contain carbonate monomer units greater than 50 mole percentages, about 75 mole percentages or more carbonate monomer units, about 80 mole percentages or more carbonate monomer units or about 85 mole percentages or more carbonate monomer units. Copolycarbonate can contain about 99 mole percentages or less carbonate monomer units, about 97 mole percentages or less carbonate monomer units or about 95 mole percentages or less carbonate monomer units. Copolycarbonate can contain about 1 mole percentage or more comonomer monomer units, about 3 mole percentages or more comonomer monomer units or about 5 mole percentages or more comonomer monomer units. Copolycarbonate can contain comonomer monomer units less than 50 mole percent, about 25 mole percent or less comonomer monomer units, about 20 mole percent or less comonomer monomer units or about 15 mole percent or less comonomer monomer units. Polycarbonate units can contain aromatic units in the main chain of polymer. Polycarbonate used herein can include any amount of original polycarbonate and/or waste polycarbonate as required to achieve desirable flame retardancy, molecular weight and/or other required properties. For example, composition of the present invention and polymer can include original polycarbonate or waste polycarbonate of about 10 percent or more, about 30 percent or more or about 50 percent or more. Composition of the present invention and polymer can include original polycarbonate or waste polycarbonate of about 100 percent or less, about 80 percent or less or about 60 percent or less.

The production of polycarbonates is effected, for example, by the phase boundary process, by reacting diphenols with carbonate halides, preferably phosgene, and/or with aromatic dicarboxylic acid dihalides, preferably benzene dicarboxylic acid dihalides, optionally with chain terminators such as monophenols and optionally with trifunctional branching agents or branching agents with a functionality higher than three, such as triphenols or tetraphenols. The diphenols which can be used to produce aromatic polycarbonates and/or aromatic polyester carbonates may correspond to formula I wherein A represents a single bond, a C _1-5 alkylene group, a C _2-5 alkylene group, a C _5-6 cycloalkylene group, -O-, -SO-, -CO-, -S-, -SO ₂ - or a C _6-12 aryl group, to which other aromatic rings containing heteroatoms as appropriate may be condensed, or a free radical of formula II or III: II or III wherein B is independently in each case hydrogen, C _1-12 alkyl, preferably methyl, or a halogen, preferably chlorine and/or bromine; x is independently in each case 0, 1 or 2; p is 0 or 1; R ^c and R ^d are independently of each other and can be selected individually for each X ¹ and are hydrogen or C _1-6 alkyl, preferably hydrogen, methyl or ethyl; X ¹ represents carbon; and m represents an integer from 4 to 7, preferably 4 or 5, provided that R ^c and R ^d simultaneously represent an alkyl group on at least one X ¹ atom.

Exemplary diphenols are hydroquinone, resorcinol, dihydroxybiphenyl, bis(hydroxyphenyl)-C _1-5 alkane, bis(hydroxyphenyl)-C _5-6 cycloalkane, bis(hydroxy-phenyl)ether, bis(hydroxy-phenyl)sulfide, bis(hydroxyphenyl)ketone, bis(hydroxy-phenyl)sulfide and 4,4″-bis(hydroxyphenyl)diisopropylbenzene, and derivatives thereof having brominated and/or chlorinated nuclei. Particularly preferred diphenols are 4,4'-dihydroxybiphenyl, bisphenol A, 2,4-bis(4-hydroxyphenyl)-2-methyl-butane, 1,1-bis(4-hydroxyphenyl)-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane, 4,4-dihydroxydiphenyl sulfide and 4,4-dihydroxydiphenyl sulfide, as well as dibrominated or dichlorinated and tetrabrominated or tetrachlorinated derivatives thereof, such as 2,2-bis(3-chloro-4-hydroxy-phenyl)propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl)propane or 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane. 2,2-bis-(4-hydroxyphenyl)propane (bisphenol A) is particularly preferred. The diphenols can be used alone or as any mixture. The diphenols are known in the literature or can be obtained by methods known in the literature. In addition to bisphenol A homopolycarbonate, exemplary polycarbonates include copolycarbonates of bisphenol A and other disclosed diphenols (such as 2,2-bis(3,5-dibromo-4-hydroxyphenyl)-propane) in an amount of up to 15 mole percent relative to the molar sum of the diphenols.

In order to end-cap, branch or extend the polycarbonate used in the present disclosure, one or more functional compounds may be used in combination with one or more reactive siloxane compounds. The functional compound may include one or more chain extenders, chain terminators, branching agents or a combination of the two. As used herein, the functional compound ends-caps, extends or branches one or more polycarbonate chains without being bound to or with the and/or pro-driver and/or reactive siloxane compound. Functional compounds may be added to the recovery solution individually or continuously one at a time over one or more time periods to effect branching and/or chain expansion and subsequent chain termination and to achieve a desired molecular weight and associated properties. One or more functional compounds may be added to the recovery solution in an amount sufficient to reduce the amount of hydroxyl groups to a desired level, to cause chain expansion and/or branching of the polycarbonate. One or more functional compounds may be added to the recovery solution in an amount of about 0.01 weight percent or more, about 0.1 weight percent or more, or about 0.5 weight percent or more, based on the total weight of the waste polycarbonate in the recovery solution. One or more functional compounds may be added to the recovery solution in an amount of about 10 weight percent or less, about 5 weight percent or less, or about 1 weight percent or less, based on the total weight of the waste polycarbonate in the recovery solution.

The chain terminator can be configured to react with at least one free hydroxyl and/or carboxyl group of one or more spent polycarbonates and/or siloxane-modified polycarbonates to chain terminate the non-polycarbonate compounds to remove free hydroxyl and/or carboxyl groups or both. The chain terminator described herein can be configured to bind to one or more hydroxyl or carboxyl groups in the recovery solution so that the free hydroxyl and/or carboxyl groups do not break one or more polycarbonate polymers. The chain terminator can include one or more groups that can react with one or more hydroxyl or carboxyl groups in a condensation reaction. The chain terminator can be used to chain terminate one or more spent polycarbonates and/or siloxane-modified polycarbonates. Chain terminators can be used in combination with one or more non-polycarbonate compounds to remove free hydroxyl and/or carboxyl non-polycarbonate compounds (e.g., carboxyl and/or hydroxyl-containing compounds) from the recovery solution, and/or prevent polycarbonate chains from breaking due to undesirable interactions of hydroxyl and/or carboxyl groups. Chain terminators can be any compound that reacts with hydroxyl and/or carboxyl groups, which groups do not negatively affect the usefulness of the resulting polycarbonate. Exemplary chain terminators can include one or more isocyanates, amines, esters, epoxides, anhydrides, carboxylic acids, or any combination thereof.

The chain terminator may include one or more phenolic compounds. The phenolic compounds may include phenol, p-chlorophenol, p-tert-butylphenol, 4-(1,3-dimethyl-butyl)-phenol and 2,4,6-tribromophenol; long chain alkylphenols such as monoalkylphenols or dialkylphenols containing a total of 8 to 20 carbon atoms in their alkyl substituents, exemplary phenolic compounds are 3,5-di-tert-butylphenol, p-isooctylphenol, p-tert-octylphenol, p-dodecylphenol, 2-(3,5-dimethylheptyl)-phenol and 4-(3,5-dimethylheptyl)-phenol.

The branching agent used in the present disclosure can be any compound capable of reacting with three or more carboxyl groups and/or hydroxyl groups on the same or separate polycarbonate compounds, respectively. The branching agent can have a functionality of three or more, four or more, five or more, or six or more. Functionality is a measure of the ability to bind to individual hydroxyl and/or carboxyl groups. The branching agent can react with three or more, four or more, five or more, or a plurality of hydroxyl and/or carboxyl groups. The polycarbonate can be branched, for example, by incorporating about 0.05 to about 2.0 mole percent of a trifunctional compound or a compound having a functionality higher than three (e.g., a compound containing three or more phenolic groups) relative to the total amount of branching agent used. Branched polycarbonates useful in the disclosed compositions can be prepared by known techniques, for example, several methods are disclosed in USP 3,028,365; 4,529,791; and 4,677,162; which are incorporated herein by reference in their entirety. Exemplary branching agents include trifunctional or polyfunctional carboxylic acid chlorides such as benzene trimesic acid trichloride, cyanuric acid trichloride, 3,3'-,4,4'-benzophenone tetracarboxylic acid tetrachloride, 1,4,5,8-naphthalene-tetracarboxylic acid tetrachloride or benzene tetracarboxylic acid tetrachloride in an amount of about 0.01 to about 1.0 mole percent (relative to the diphenol used), or trifunctional or polyfunctional phenols such as phloroglucinol, 4,6-dimethyl-2,4,6-tris(4-hydroxyphenyl)-2-heptene, 4,4 ... tris(4-hydroxyphenyl)-phenyl-methane, 2,2-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane, 2,4-bis[1-(4-hydroxyphenyl)-1-methyl-ethyl]phenol, tetrakis(4-hydroxyphenyl)-methane, 2,6-bis(2-hydroxy-5-methyl-benzyl)-4-methyl-phenol, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane or tetrakis(4-[1-(4-hydroxyphenyl)-1-methylethyl]-phenyl-oxy)-methane. Phenolic branching agents can be placed in the reaction vessel together with the diphenols. Acid chloride branching agents can be introduced together with the acid chlorides.

Chain extenders can include any compound having a group sufficient to bind two individual polycarbonate chains together. Chain extenders can be configured to react with two individual carboxyl groups and/or hydroxyl groups to expand polycarbonate, or remove free carboxyl groups and/or hydroxyl groups in the recovery solution. Chain extenders can contain at least two groups sufficient to react with two different polycarbonate chains and/or free hydroxyl groups and/or carboxyl groups, respectively. Chain extenders can be used to combine with one or more non-polycarbonate compounds to remove free hydroxyl groups and/or carboxyl groups from the recovery solution, and/or prevent polycarbonate chains from breaking due to undesired interactions of hydroxyl groups and/or carboxyl groups. Combinations of chain extenders can be used to combine polycarbonates with different end groups. Examples of chain extenders may include two or more functional groups including isocyanate, amine, ester, epoxide, anhydride, carboxylic acid, or any combination thereof.

The solvent system may include one or more solvents or only one solvent, such as a polycarbonate solvent. The solvent system may include two mutually soluble solvents present in multiple concentrations. The solvent system may include two or more solvents, the presence of which makes a portion of the solvent system include some water dissolved in one or more polycarbonate solvents and some water separated from the polycarbonate solvent. The mutual solubility of the two solvents may be affected or changed based on the temperature or pressure applied to the recovery solution. The solvent system may include polycarbonate and water in a mutual solubility amount, such as about 0.6 weight percent or less, about 0.4 weight percent or less, about 0.2 weight percent or less, or about 0.1 weight percent based on the total weight of the solvent system or the recovery solution. In some examples, water can be present in the solvent system in an amount that exceeds the amount of water that is miscible in the polycarbonate solvent. Where water is involved in one or more of the reactions described herein, such as the reaction with a precursor siloxane compound to form a reactive siloxane compound, the water can react within the polycarbonate solvent, and as the reaction occurs, excess water can dissolve into the polycarbonate solvent. One or more separation steps can be used to remove an undesirable amount of water or substantially all of the water (e.g., until the solvent system has 0.1 or less, 0.01 or less, or 0.001 or less water in the solvent system). Water can be removed from the solvent system before or after the reactive polycarbonate is dissolved. In place of water, the solvent system may include one or more other polar protic solvents configured to adjust the miscibility of the components in the recovery solution or to participate in one or more reactions, such as during the formation of a siloxane-modified polycarbonate or a reactive siloxane compound. Examples of other polar protic solvents may include methanol, ethanol, n-propanol or isopropanol, n-butanol or tert-butanol, acetic acid, ammonia, formic acid, or any combination thereof.

The polycarbonate solvent is used to dissolve solid polycarbonate from the waste feedstock. The polycarbonate solvent may dissolve one or more waste polycarbonates from the waste feedstock without dissolving one or more other non-polycarbonate polymers and other materials that may negatively impact the use of recycled polycarbonate present in the waste stream. The polycarbonate solvent may have a boiling point sufficient to be heated to a temperature that does not break the polycarbonate chains. The polycarbonate solvent may have a boiling point of about 25°C or more, about 40°C or more, or about 60°C or more. The polycarbonate solvent may have a boiling point of about 160°C or less, about 120°C or less, or about 80°C or less. The polycarbonate solvent may be any solvent that preferentially dissolves polycarbonate relative to other polymers and materials present in the waste stream that may negatively impact the use of the recycled polymer. The polycarbonate solvent may be a polar aprotic solvent. The polycarbonate solvent may contain at least one halogen atom. The polycarbonate solvent may contain one or more reactive protons. The polycarbonate solvent may be free of one or more carboxyl and/or hydroxyl groups. The polycarbonate solvent may not react with one or more carboxyl and/or hydroxyl groups. The polycarbonate solvent may be immiscible with polar protic solvents such as water, so that the polycarbonate solvent can be used in a devolatilization process to recover the polycarbonate solvent and the siloxane-modified polycarbonate in solid form alone. The polycarbonate solvent may include one or more of chloroform, dichloromethane, chlorobenzene, dichlorobenzene, tetrahydrofuran, 2-methyltetrahydrofuran, N-methyl-2-pyrrolidone, dimethylformamide, 1,4-dioxane, methyl ethyl ketone, ethyl acetate:ethanol (3:1, binary solvent), dimethyl sulfoxide, or any combination thereof.

The present disclosure provides techniques for modifying reactive polycarbonate polymers and oligomers with reactive siloxane compounds to formulate polymers with imparted fire resistance, higher molecular weight, fewer hydroxyl and/or carboxyl groups, and/or reduced hydroxyl and/or carboxyl groups in polymer compositions. By integrating the siloxane compound within the polycarbonate chain, siloxane units can be added within and/or along the backbone of the polycarbonate, resulting in one or more properties of the siloxane-modified polycarbonate. In addition, to simplify the steps of recycling waste polycarbonate, the reactive siloxane compound can be formed in situ and/or using the same solvent system as the solvent system used to dissolve the waste polycarbonate, so that separation steps and handling steps can be reduced. Using these techniques, siloxane-modified polycarbonates can be combined with additional techniques for integrating chain extenders and branching agents to achieve polycarbonates with desirable flame retardancy, reduced hydroxyl and/or carboxyl groups, and increased molecular weight in polymer compositions.

Waste polycarbonate (e.g., reactive polycarbonate) includes reactive groups formed by degradation of the original polycarbonate over time. The reactive siloxane compounds disclosed herein can easily contact the reactive groups of the waste polycarbonate and integrate into the existing waste polycarbonate to impart molecular weight and adjust the properties of the polycarbonate.

The reactive polycarbonate may include one or more reactive groups (e.g., carboxyl, hydroxyl, and/or phenolic groups) configured to react with the acetyloxy, methoxy, ethoxy, halogenide, and/or hydrogen groups of the reactive siloxane compound. In the case where the reactive polycarbonate is a recycled and unmodified polycarbonate polymer and/or oligomer, the reactive polycarbonate may include one or more hydroxyl, phenolic, or carboxyl groups at the terminal ends or along the backbone resulting from natural degradation of the polymer over time. Natural degradation may occur due to exposure to extreme temperatures and/or sunlight (i.e., UV radiation). Prior to contacting the reactive siloxane compound with the reactive polycarbonate, the reactive polycarbonate or the original polycarbonate described herein may be modified so that free hydroxyl, phenolic and/or carboxyl groups are introduced into the polymer at the terminal and/or along the backbone, so that the polycarbonate can react with the acetyloxy, methoxy, ethoxy, halogenide and/or hydrogen groups of the reactive siloxane compound. For example, the waste polycarbonate or the original polycarbonate may be hydroxylated by any means sufficient to form a reactive polycarbonate comprising one or more hydroxyl, phenolic and/or carboxyl groups. Hydroxylation of the original polycarbonate and/or the reactive polycarbonate can be carried out by oxidizing the polycarbonate, by exposing the polycarbonate to ultraviolet light to degrade the polycarbonate, and/or by hydrolyzing one or more of the original polycarbonate and/or the waste polycarbonate. The reactive polycarbonate can contain any amount of hydroxyl and/or carboxyl groups at the terminal or along the main chain, and the reactive siloxane compound can be combined with the hydroxyl and/or carboxyl groups so that the free hydroxyl and/or carboxyl groups are reduced or eliminated in the modified siloxane compound. In addition, the reactive polycarbonate in the composition can include undesirable amounts of hydroxyl and/or carboxyl compounds, which can be reduced by introducing the separation step described herein and/or the reactive siloxane compound.

By adjusting the reactive groups of the reactive polycarbonate, the reactive siloxane compound and the desired functional compound can be bonded to the polycarbonate in a desired sequence, so as to impart flame retardancy, reduce the hydroxyl and/or carboxyl groups in the polymer composition, repair and/or control the molecular weight, and/or remove hydroxyl, phenolic and carboxyl groups from the reactive polycarbonate. The reactive siloxane compound and the reactive polycarbonate can be first contacted to form a bond having a chain sequence of reactive siloxane compound-reactive polycarbonate, and then the functional compound can be contacted with the reactive siloxane compound-reactive polycarbonate to form a siloxane-modified polycarbonate having a chain sequence of functional compound-reactive siloxane compound-reactive polycarbonate. The functional compound and the reactive polycarbonate may be first contacted to form a bond having a chain sequence of functional compound-reactive polycarbonate, and then the functional compound may be contacted with the flame functional compound-reactive polycarbonate to form a chain polycarbonate having a reaction sequence of reactive siloxane compound-functional compound-reactive polycarbonate. In the case of a siloxane-modified polycarbonate having a chain sequence of reactive siloxane compound-functional compound-reactive polycarbonate or a siloxane-modified polycarbonate having a chain sequence of functional compound-reactive siloxane compound-reactive polycarbonate, the siloxane-modified polycarbonate may then be contacted with additional reactive siloxane compounds, functional compounds and/or reactive polycarbonate polymers or oligomers or any combination thereof to impart the desired flame resistance within the polymer chain, to achieve the desired molecular weight, and/or to remove hydroxyl, phenolic and/or carboxyl groups from the reactive polycarbonate to form the siloxane-modified polycarbonate. At any of the free reactive groups of the reactive polycarbonate, a functional compound or a reactive siloxane compound may be added to terminate or bond two or more polycarbonate chains together.

As used herein, the siloxane modifier is configured to integrate siloxane units within and/or along the backbone of the siloxane-modified polycarbonate. The siloxane modifier can be any siloxane compound comprising siloxane repeating units including at least one acetyloxy, methoxy, ethoxy, halide and/or hydrogen group configured to react with the hydroxyl, carboxyl and/or phenolic groups of the reactive polycarbonate. The siloxane modifier can contain, for example, between one and 100 siloxane units. The siloxane modifier can include a pro-driver siloxane compound and/or a reactive siloxane compound. The siloxane modifier can be contacted with the reactive polycarbonate before or after the reactive polycarbonate is dissolved in the solvent system. The siloxane modifier can be configured to react in the solvent system to form a multi-unit siloxane.

The pro-siloxane compound may serve as the basis for the reactive siloxane compound. The pro-siloxane compound may comprise a silane or silane group substituted with at least one halide, acetyloxy, ethoxy and/or methoxy group and optionally one or more hydrogen and/or alkyl groups. The pro-siloxane comprising at least one halide, acetyloxy, ethoxy and/or methoxy group may be configured to react with one or more water molecules dissolved in a solvent system to form a silane having one or more terminal halide, acetyloxy, ethoxy and/or methoxy groups. The pro-siloxane compound may have a structure according to the following formula: wherein at least one ^Ra comprises hydrogen, methoxy, acetoxy and/or a halide group, and each ^Ra may independently comprise a halide, methoxy, ethoxy, acetoxy, hydrogen or a linear or branched alkyl, aryl, alkyl-aryl, aryl-alkyl, heteroalkyl or heteroaryl group or any combination thereof.

After reacting with water molecules, one or more acids may be generated as byproducts in the formation of the reactive siloxane compound or siloxane-modified polycarbonate. The one or more acids may be removed from the solvent system by one or more scavengers as described herein before, during, or after contacting the reactive polycarbonate with the solvent system. The precursor siloxane compound may be configured to introduce siloxane units along or within the backbone of the reactive polycarbonate, resulting in the formation of a siloxane-modified polycarbonate having an increased molecular weight relative to the reactive polycarbonate. The pro-driver siloxane may include any number of halides, acetyloxy, ethoxy and/or methoxy groups configured to react with one or more free hydroxyl, carboxyl and/or phenolic groups of the reactive polycarbonate. The pro-driver siloxane compound may include monomethoxysilane, dimethoxysilane, trimethoxysilane and/or tetramethoxysilane. The pro-driver siloxane compound may include monoethoxysilane, diethoxysilane, triethoxysilane and/or tetraethoxysilane. The pro-driver compound may include monoacetoxysilane, diethoxysilane, triacetoxysilane and/or tetraacetoxysilane. The precursor siloxane compound may include monohalogenated silane, dihalogenated silane, trihalogenated silane and/or tetrahalogenated silane. The precursor siloxane compound may be contacted with the solvent system before, during or after the reactive polycarbonate is dissolved in the solvent system. The precursor siloxane compound may be soluble in the polycarbonate solvent or may be immiscible with the polycarbonate solvent. The precursor siloxane compound may be added to the solvent system in any amount sufficient to integrate the siloxane unit into the reactive polycarbonate. In some examples, the precursor siloxane compound may be directly connected to the reactive polycarbonate before the reactive siloxane compound is formed. Some pro-siloxane compounds can react with water to form longer chain reactive siloxane compounds, and some pro-siloxane compounds can react with reactive polycarbonates to end-cap, chain-extend, crosslink or branch the reactive polycarbonates and form siloxane-modified polycarbonates. The pro-siloxane compounds can be added to the solvent system in an amount of about 0.1 weight percent or more, about 1 weight percent or more, or about 3 weight percent or more based on the total weight of the solvent system. The pro-siloxane compounds can be added to the solvent system in an amount of about 10 weight percent or less, about 8 weight percent or less, or 5 weight percent or less.

Reactive siloxane compounds are used to integrate siloxane units into reactive polycarbonates to form siloxane-modified polycarbonates. The reactive siloxane can be configured to bind to the reactive polycarbonate at one or more positions on the reactive polycarbonate, optionally in the presence of a catalyst suitable for forming siloxane-modified polycarbonate. Reactive positions include free carboxyl, hydroxyl, phenolic and/or alkenyl groups along the backbone of the polycarbonate or at the ends of the polycarbonate. The reactive siloxane compound can include any group configured to react and bind to the reactive polycarbonate at the reactive position. Examples of groups configured to react at or bind to the reactive position can include methoxy, ethoxy, acetyloxy, halides and/or hydrogen groups. The reactive siloxane compound may include any number of halides, methoxy groups, ethoxy groups, acetoxy groups, and/or hydrogen groups configured to react or bind to reactive positions of the reactive polycarbonate. The reactive siloxane compound may include a plurality of methoxy groups, ethoxy groups, acetoxy groups, halides, and/or hydrogen groups configured to end-cap, chain-extend, branch, and/or cross-link the reactive polycarbonate to achieve the desired molecular weight of the siloxane-modified polycarbonate. The reactive siloxane compound may include methoxy groups, acetoxy groups, ethoxy groups, halides, and/or hydrogen groups at different ends, on different silicon atoms, or on the same silicon atom. The reactive siloxane compound may include one or more, two or more, three or more, four or more, five or more or a plurality of methoxy, acetyloxy, ethoxy, halide and/or hydrogen groups configured to end-cap, chain-extend, branch and/or cross-link the reactive polycarbonate. The reactive siloxane compound may include any number of siloxane units sufficient to introduce molecular weight enhancement, impart flame resistance, reduce hydroxyl and/or carboxyl groups, or any combination thereof, into the polymer composition. The reactive siloxane compound may include 1 or more, 10 or more, or 20 or more siloxane units. The reactive siloxane compound may include 100 or less, 70 or less, or 50 or less siloxane units. The reactive siloxane compound can be added to the solvent system in any amount sufficient to increase the molecular weight of the reactive polycarbonate and/or remove or combine with carboxyl and/or hydroxyl compounds in the recovery solution. The reactive siloxane compound can be added to the solvent system in an amount of about 0.1 weight percent or more, about 1 weight percent or more, or about 3 weight percent or more based on the total weight of the solvent system. The reactive siloxane compound can be added to the solvent system in an amount of about 10 weight percent or less, about 8 weight percent or less, or about 5 weight percent or less. The reactive siloxane compound can additionally or alone reduce the amount of hydroxyl compounds in the recovery solution. Reactive siloxane compounds can be used to combine polycarbonate polymers and/or oligomers together and/or with hydroxyl-containing compounds so that the final polycarbonate composition contains fewer free hydroxyl and/or carboxyl groups.

The reactive siloxane compound may have a structure according to the following formula: wherein m is an integer from 1 to 100, at least one ^Ra comprises a methoxy group, an ethoxy group, an acetyloxy group, a halide and/or a hydrogen group, and wherein each ^Ra may independently comprise a methoxy group, an acetyloxy group, an ethoxy group, a halide, a hydrogen group or a linear or branched alkyl group, an aryl group, an alkyl-aryl group, an aryl-alkyl group, a heteroalkyl group or a heteroaryl group or any combination thereof.

Allyl halides can be configured to react with the hydroxyl and/or phenolic groups of polycarbonates to form acid and vinyl ether terminated polycarbonates. Where the siloxane compound is terminated by or includes at least one hydrogen atom, the siloxane compound can be configured to react with the vinyl group of the vinyl ether terminated polycarbonate to form a siloxane-modified polycarbonate, optionally in the presence of a suitable catalyst. The siloxane units of the siloxane-modified polycarbonate can be linked to the polycarbonate units via one or more alkyl, aryl, alkyl-aryl or arylalkyl groups that are the residues of the allyl halides therebetween. The allyl halides can be added to the solvent system in an amount sufficient to extend, terminate and/or branch the reactive polycarbonate. The allyl halide may be added at a weight percentage of about 0.1 weight percent or more, about 0.5 weight percent or more, or about 1 weight percent or more based on the total weight of the solvent system. The allyl halide may be added at a weight percentage of about 5 weight percent or less, about 3 weight percent or less, or about 2 weight percent or less based on the total weight of the solvent system. The allyl halide may be added to the solvent system at a molar ratio relative to the reactive siloxane compound such that a desired molecular weight increase occurs. The allyl halide and the reactive siloxane compound may be contacted in the solvent system at a molar ratio of about 4:1 or greater, about 3:1 or greater, or about 2:1 or greater. The allyl halide and the reactive siloxane compound may be contacted in a solvent system at a molar ratio of about 1:1 or less, about 1:2 or less, or about 1:4 or less. The allyl halide may have any structure connecting the olefin and the halide. The allyl halide may have any structure with one end capped by the halide and the other end capped by the olefin. The allyl halide may include one or more linear or branched alkyl, aryl, alkylaryl, arylalkyl, or any combination thereof between the olefin and the halide. The allyl halide may have a structure according to the following formula: wherein Ha is any halide, wherein R ^b is one or more linear or branched alkyl, aryl, alkylaryl, arylalkyl or any combination thereof, and wherein x is an integer from 1 to 10.

Vinyl ether terminated polycarbonates may have a structure according to the following formula: wherein R ^b is one or more linear or branched alkyl, aryl, alkylaryl, aralkyl or any combination thereof, wherein x is an integer from 1 to 10, and wherein PC is a residue of a reactive polycarbonate.

After contacting the vinyl ether terminated polycarbonate with a reactive siloxane compound, the siloxane modified polycarbonate may have a structure according to the following formula: wherein R ^b is one or more linear or branched alkyl, aryl, alkylaryl, arylalkyl or any combination thereof, wherein x is an integer from 1 to 10, wherein m is an integer from 1 to 100, at least one ^Ra is a hydrogen atom or a halide atom, wherein each ^Ra may independently comprise a halide, hydrogen or a linear or branched alkyl, aryl, alkyl-aryl, aryl-alkyl, heteroalkyl or heteroaryl group or any combination thereof, and wherein PC is a residue of a reactive polycarbonate.

After the reactive siloxane compound or siloxane-modified polycarbonate is formed, one or more acids may be generated as byproducts of the reaction. The acid as described herein may comprise any acid compound, including halides, methoxy, ethoxy and/or acetoxy groups, such as halogenated acids or acetic acid. The halogenated acid may include hydrochloric acid, hydrobromic acid, hydrofluoric acid, or any combination thereof. The acid formed herein may be removed before, during, or after the addition of the reactive polycarbonate or before, during, or after the formation of the siloxane-modified polycarbonate by any separation step known to those skilled in the art.

The present disclosure provides a polymer composition comprising a siloxane-modified polycarbonate as described herein. Specifically, the residue of the reactive siloxane compound may be attached to the polycarbonate unit at an oxygen atom along the main chain of the polycarbonate segment or at the end of the polycarbonate segment. After the siloxane-modified polycarbonate is formed, the siloxane-modified polycarbonate may be removed from a recovery solution via a separation step described herein to remove the polycarbonate from a recovery solution or other liquid. The siloxane-modified polycarbonate and/or polymer composition may be substantially free of a solvent system and/or hydroxyl and/or carboxyl-containing compounds (i.e., containing 1 weight percent or less, 0.1 weight percent or less, or 0.01 weight percent or less). Siloxane-modified polycarbonates may contain one or more polycarbonate segments connected by the residue of a reactive siloxane compound, so as to form a siloxane-polycarbonate copolymer. Siloxane-modified polycarbonates may be branched or unbranched siloxane-polycarbonate copolymers of repeating siloxane units and polycarbonate segments. The amount of branching may be derived from a reactive siloxane compound having three or more methoxy, ethoxy, acetyloxy, halide and/or hydrogen groups connecting three different polycarbonate segments. In other examples, the amount of branching may be derived from a reactive polycarbonate having at least three hydroxyl and/or carboxyl groups configured to be bonded to a reactive siloxane group. The polycarbonate segments may be based on the residues of spent polycarbonate polymers or oligomers having any number of polycarbonate repeating units. For the siloxane blocks, the siloxane-modified polycarbonate may include any number of siloxane units in each block. Each siloxane block may include one or more, four or more, or ten or more siloxane units. Each siloxane block may include one hundred or fewer, seventy-five or fewer, or fifty or fewer siloxane units.

The present application provides polymerizable compositions including any number of the components described herein, which are present in waste materials or used to form siloxane-modified polycarbonates. For example, the polymerizable composition may include one or more acids, siloxane modifiers (e.g., reactive siloxane compounds and/or precursor siloxane compounds), reactive polycarbonates and/or raw polycarbonates, catalysts configured to form siloxane-modified polycarbonates, solvent systems, non-polycarbonate compounds, waste materials, or any combination thereof. One or more reactive polycarbonates and siloxane modifiers may react in the solvent system of the polymerizable composition to form one or more siloxane-modified polycarbonates.

The polycarbonate or polymerizable composition may contain waste polycarbonate, polycarbonate segments, or residues thereof in any amount sufficient to achieve the desired composition of the recycled component. For example, the polycarbonate or polymerizable composition may include about 5 percent or more, about 15 percent or more, or about 25 percent or more of waste polycarbonate, polycarbonate segments, or residues thereof. The polycarbonate or polymerizable composition may include about 100 percent or less, about 80 percent or less, or about 50 percent or less of waste polycarbonate, polycarbonate segments, or residues thereof.

In downstream process uses, the siloxane-modified polycarbonate may be contacted with one or more compounds required to make a downstream product or composition. The siloxane-modified polycarbonate may be mixed or blended with one or more other polymers or virgin polycarbonate to achieve desired properties. The other polymers may include polystyrene, styrene acrylonitrile, acrylonitrile butadiene, styrene, high impact polystyrene, polymethyl methacrylate, polyolefins, or any combination thereof. The siloxane-modified polycarbonate may be mixed or blended with one or more additives sufficient to achieve the desired properties using known techniques for blending additives with polymeric compositions. The additives may include one or more of fillers, flame retardants, pigments, UV stabilizers, antioxidants, release agents, dyes, or any combination thereof.

Any technique or combination of techniques may be used to contact the polycarbonate solvent, the precursor siloxane compound and/or the reactive siloxane compound, the reactive polycarbonate and/or the waste raw material such that the polycarbonate solvent dissolves the components in the recovery solution, or the components are dispersed in the recovery solution, such that the desired surface contact is achieved between the components.

The recovery solution may be contacted in any enclosure sufficient to contain fluids (e.g., liquids and/or gases). The recovery solution may be contacted in a sealed enclosure configured to contain the fluids and gases such that the waste feedstock and/or reactive polycarbonate may be mixed with the fluids and gases to achieve a desired dissolution level of the reactive polycarbonate and/or the waste feedstock. The waste feedstock may be moved into the sealed enclosure through the access point and moved into contact with the polycarbonate solvent such that minimal or no polycarbonate solvent is lost through the access point as the waste feedstock is moved into and out of the sealed enclosure.

The recovery solution can be formed and mixed in a housing that is configured to apply heating and cooling in a series of sections within the housing so that the housing can apply liquid and gaseous polycarbonate solvents at different locations. The housing can include a bottom section and a middle section, each of which can be heated as appropriate, and a top section that is cooled as appropriate, wherein the waste feedstock and/or reactive polycarbonate can move into the housing at any section and volatilize the polycarbonate solvent when heat is applied in the middle section or the bottom section, and the top section cools the solvent so that the solvent does not escape through the top of the housing.

Heat and/or agitation may be applied to the recovered solution before, during, or after contact with the polycarbonate solvent, solvent system, and waste materials to improve dissolution time or mixing of the reactive polycarbonate and/or pro-driver siloxane compound and/or reactive siloxane compound into the polycarbonate solvent. Heat and/or agitation may be applied in combination, individually, or sequentially to achieve a desired concentration level, saturation, dispersion, mixing time, and/or dissolution time of the reactive polycarbonate and/or pro-driver siloxane compound and/or reactive siloxane compound in the polycarbonate solvent. Heating and/or agitation, alone or in combination, may provide a technique for controlling the physical state (e.g., gas, liquid, solid) of the polycarbonate solvent, reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound.

The housing may be equipped with any instrument sufficient to apply heating and/or cooling to control the physical state of the polycarbonate solvent and improve the dissolution and mixing of the reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound. Instruments that apply heating and/or cooling by any means sufficient to adjust the temperature of the recovery solution may be available. The housing may be equipped with one or more, two or more, three or more, or a plurality of heating instruments and/or cooling instruments to manipulate the temperature of the recovery solution. The instruments for heating and cooling may be in the same section or may be located in separate locations and/or sections so that the state of the recovery solution is controlled and/or the polycarbonate solvent is prevented from escaping the housing. Agitation may be applied to a solvent system or polycarbonate solvent that is in a liquid state and separately in a gaseous state. Any type of agitation that enhances the dissolution of reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound in polycarbonate solvent may be provided. The housing may be equipped with a plurality of instruments configured to apply a single state of agitation. The housing may be equipped with an ultrasonic treatment device (i.e., for applying ultrasound) and a stirring device so that two or more techniques may be used to improve agitation and, therefore, improve the dissolution of waste polycarbonate in polycarbonate solvent. Examples of agitators may include ultrasonic generators, impellers, magnetic stirrers, vortices, rockers, oscillators, or any combination thereof.

Agitation can act to move dissolved waste polycarbonate molecules in a direction away from the waste feedstock so that additional waste polycarbonate can be dissolved in the polycarbonate solvent and the entire recycled solution reaches the desired total concentration or saturation in a shorter time. Agitation can be applied to the polycarbonate solvent around the waste feedstock and/or reactive polycarbonate to mix the polycarbonate solvent and reduce the local saturation of the polycarbonate at one location in the recycled solution. Agitation can be applied for any period of time or with any force sufficient to move the reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound molecules within the polycarbonate solvent and achieve the desired concentration or saturation in the recycled solution. A combination of agitation may be applied to the polycarbonate solvent and the waste materials, reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound or a container holding the waste materials, so that polycarbonate molecules move in the polycarbonate solvent. The container holding the waste materials may be shaken or agitated when ultrasound is applied from an external ultrasonic treatment device, which improves the movement of the polycarbonate solvent around the waste materials. Examples of agitation may include cavitation, vortexing, oscillation, shaking, rotation, stirring or any combination thereof.

The application of heat can act to raise the temperature of the polycarbonate solvent to the boiling point of the polycarbonate solvent or below, so the disclosed method can achieve the desired level of concentration, saturation, mixing time and/or dissolution time of the reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound in the polycarbonate solvent. Heat can be applied so that the polycarbonate solvent boils and a portion of the polycarbonate solvent is converted to gaseous form. When heat is applied to convert the polycarbonate solvent to gaseous form, the vaporized polycarbonate solvent can be contained in a sealed housing or chamber above the recovery solution and/or waste raw materials as the waste polycarbonate and/or reactive polycarbonate are dissolved in the polycarbonate solvent. Heat can be applied up to the boiling temperature of the polycarbonate solvent without breaking one or more polycarbonate chains. Heat can be applied to the polycarbonate solvent at a temperature of about 30°C or more, about 40°C or more, or about 50°C or more. Heat can be applied to the polycarbonate solvent at a temperature of about 160°C or less, about 120°C or less, or about 80°C or less.

After contacting the polycarbonate solvent and the waste raw materials to form a recovery solution, once the desired concentration of the waste polycarbonate and/or reactive polycarbonate is achieved in the recovery solution, the waste raw materials can be removed from the recovery solution. The waste raw materials can be removed by any means sufficient to separate solids from liquids. The waste raw materials can be removed from the liquid recovery solution by an appropriate container. The waste raw materials can be removed from the recovery solution, then washed with a gas phase polycarbonate solvent, and removed from the housing containing the recovery solution. The waste polycarbonate and/or reactive polycarbonate can have any desired concentration in the polycarbonate solvent so that the waste polycarbonate can be repaired by one or more functional compounds in a subsequent step. The waste polycarbonate and/or reactive polycarbonate may have a concentration in the polycarbonate solvent that is equal to or less than the saturation level at or just below the boiling point of the polycarbonate solvent. The waste polycarbonate and/or reactive polycarbonate may have a concentration in the polycarbonate solvent of about 1 weight percent or more, about 5 weight percent or more, or about 10 weight percent or more. The waste polycarbonate may have a concentration in the polycarbonate solvent of about 50 weight percent or less, about 30 weight percent or less, or about 20 weight percent or less.

The polycarbonate solvent, reactive polycarbonate, pro-driver siloxane compound and/or reactive siloxane compound and/or waste materials may be contacted for any period of time sufficient to dissolve and/or mix the reactive polycarbonate and/or pro-driver siloxane compound and/or reactive siloxane compound in the polycarbonate solvent. The amount of time sufficient to dissolve the waste polycarbonate in the polycarbonate solvent at a desired concentration or to achieve saturation may depend on the agitation and/or temperature applied to the waste materials and/or polycarbonate solvent. The polycarbonate solvent and waste materials may be contacted for a period of 10 minutes or more, about 60 minutes or more, or about 90 minutes or more. The polycarbonate solvent and the waste material may be contacted for a period of 6 hours or less, about 4 hours or less, or about 3 hours or less. More than one batch of waste material, reactive polycarbonate and/or precursor siloxane compound and/or reactive siloxane compound may be contacted with and removed from the polycarbonate solvent until a desired concentration of waste polycarbonate is achieved in the recovered solution and/or a desired level of flame resistance is imparted to the polycarbonate.

The reclaimed solution may be subjected to one or more separation steps configured to remove compounds that may negatively affect the reaction in the reclaimed solution or that remain in the reclaimed solution after the reactive polycarbonate is dissolved. The reclaimed solution may be contacted with one or more scavengers configured to precipitate or render inactive one or more non-polycarbonate compounds or acids that are dissolved from the waste feedstock into the polycarbonate solvent or byproducts that form the siloxane-modified polycarbonate or reactive siloxane compounds. The reclaimed solution may be contacted with a scavenger such as an adsorbent or absorbent material configured to bind to the acid. Examples may include one or more of activated carbon, clay, zeolite, polymeric adsorbent or absorbent, alkaline wash, buffer, or any combination thereof to remove non-polycarbonate compounds found in the waste feedstock. The scavenger may include any functional group sufficient to bind to free acids, hydroxyl groups, carboxyl groups, other non-polycarbonate compounds that are susceptible to polycarbonate chain scission or are not desired in the polycarbonate composition, or a combination thereof, thereby reducing or avoiding undesirable interactions with the functional groups and/or waste polycarbonate. Examples of scavenger compounds may include one or more of hydroxides, isocyanates, amines, esters, epoxides, anhydrides, carboxylic acids, or any combination thereof. After reacting or binding with one or more non-polycarbonate compounds or acids in the recovery solution, the scavenger, adsorbent compound, and/or absorbent compound may be removed as a liquid or solid as described herein.

If non-polycarbonate compounds or acids from the waste feedstock do not precipitate with the scavenger, adsorbent material, and/or absorbent material, the non-polycarbonate compounds may be removed by one or more separation techniques configured to remove liquid from liquid, such as by solvent extraction, distillation, or any combination thereof. Solids may be present in the recovery solution due to the above precipitation by the scavenger, adsorbent material, and/or absorbent material or by movement through a plurality of perforations in a perforated container. The recovery solution may have any solid non-polycarbonate compounds removed from the recovery solution prior to adding the functional compound to avoid undesirable side reactions. The solids may be removed by any known technique sufficient to separate the solid from the liquid. Solids may be removed from the recovery solution by filtration, decanting, precipitation, settling, evaporation, centrifugation, solvent extraction, reverse osmosis, or any combination thereof. Solids may be filtered using a filter having pores with a width less than the width of a plurality of perforations. Liquids may be removed by any separation technique described herein. Some non-polycarbonate compounds that do not interfere with the polycarbonate compound or functional compound may remain in the recovery solution until the polycarbonate solvent and the siloxane-modified polycarbonate are removed.

As discussed herein, once the reactive polycarbonate is dissolved in the polycarbonate solvent, the combination of the reactive polycarbonate and the polycarbonate solvent is simultaneously or subsequently contacted with one or more reactive siloxane compounds. The one or more reactive siloxane compounds may include one or more functional groups, such as methoxy, ethoxy, acetoxy, halide and/or hydrogen groups, configured to react with one or more reactive groups (i.e., hydroxyl, carboxyl and/or phenolic groups) of the reactive polycarbonate. The reactive siloxane compound includes any functional group as discussed herein that imparts fire resistance to the polycarbonate after the reactive siloxane compound is bonded to the polycarbonate chain and a siloxane-modified polycarbonate is formed. The reactive siloxane compound can be added in an amount sufficient to achieve the desired flame resistance in the siloxane-modified polycarbonate. The desired flame resistance can be the same as or at least greater than the reactive polycarbonate or the original polycarbonate. The desired flame resistance can be achieved based on the amount of the added reactive siloxane compound or reactive siloxane compound or combination thereof present in the siloxane-modified polycarbonate. For example, at 3.0 mm, 1.6 mm, or 1.0 mm, the modified polycarbonate and/or the reactive polycarbonate can have a UL-94 vertical test flame resistance rating of V-0 or higher, V-1 or higher, or V-2 or higher.

The recovered solution may be contacted with one or more functional compounds configured to adjust the molecular weight of the reactive polycarbonate and/or siloxane-modified polycarbonate before or after contacting the reactive polycarbonate and the reactive siloxane compound. The one or more functional compounds and/or pro-driver siloxane compounds and/or reactive siloxane compounds may terminate, extend or branch the reactive polycarbonate and/or siloxane-modified polycarbonate chain to have increased molecular weight and/or properties and reduced hydroxyl and/or carboxyl groups. The one or more functional compounds and/or pro-driver siloxane compounds and/or reactive siloxane compounds may increase the number and/or weight average molecular weight of the polycarbonate. The weight and/or number average molecular weight may be increased by a certain percentage relative to the number and/or weight average molecular weight of the waste polycarbonate and/or reactive polycarbonate before the one or more functional compounds and/or precursor siloxane compounds and/or reactive siloxane compounds are added. The percentage increase may be about 5 percent or more, 20 percent or more, or about 40 percent or more. The percentage increase may be about 100 percent or less, about 75 percent or less, or about 50 percent or less. The siloxane-modified polycarbonate may have a number and/or weight average molecular weight greater than the number and/or weight average molecular weight of the waste polycarbonate and/or reactive polycarbonate. The weight average molecular weight of the siloxane-modified polycarbonate may be about 10 kg/mol or more, about 30 kg/mol or more, or about 50 kg/mol or more relative to the waste polycarbonate. The weight average molecular weight of the siloxane-modified polycarbonate relative to waste polycarbonate may be about 70 kg/mol or greater, about 90 kg/mol or greater, or about 100 kg/mol or greater. The number average molecular weight of the siloxane-modified polycarbonate relative to waste polycarbonate may be about 3 kg/mol or greater, about 10 kg/mol or greater, or about 20 kg/mol or greater. The number average molecular weight of the siloxane-modified polycarbonate relative to waste polycarbonate may be about 30 kg/mol or greater, about 40 kg/mol or greater, or about 50 kg/mol or greater. The molecular weights in the present disclosure are determined by gel permeation chromatography using narrow polystyrene standards ( Đ < 1.2) and broad range polycarbonate standards ( Đ > 1.5). After adding one or more functional compounds and/or precursor siloxane compounds and/or reactive siloxane compounds to the recycled solution, the siloxane-modified polycarbonate may have a melt flow rate sufficient to be used in downstream processes with a quality similar to that of the original polycarbonate. The melt flow rate may be similar or substantially the same as that of the original polycarbonate. Due to the modified molecular weight due to the addition of one or more functional compounds, the melt flow rate of the siloxane-modified polycarbonate may be greater than or less than the melt flow rate of the waste polycarbonate. The melt flow rate of the siloxane-modified polycarbonate may be about 1 g/10 min or greater, about 5 g/10 min or greater, or about 20 g/10 min or greater. The melt flow rate of the siloxane-modified polycarbonate may be about 80 g/10 min or less, about 60 g/10 min or less, or about 40 g/10 min or less. The melt flow rate is measured by measuring the number of grams (g/10 min) passing through a standard die (2.095 x 8 mm) for 10 minutes, as measured at 300° C. under a load of 1.2 kg according to ISO 1133 standard.

After adding the functional compound and/or the pro-driver siloxane compound and/or the reactive siloxane compound to the recovery solution, the hydroxyl and/or carboxyl groups may be present in sufficiently low amounts to reduce or avoid chain scission in the polycarbonate. After adding the functional compound and/or the pro-driver siloxane compound and/or the reactive siloxane compound to the recovery solution, the functional compound may react with the hydroxyl and/or carboxyl groups such that the recovery solution is free of or substantially free of hydroxyl and/or carboxyl groups (e.g., 0.1, 0.01, or 0.01 weight percent or less). One or more functional compounds and/or pro-driver siloxane compounds and/or reactive siloxane compounds may reduce the amount of free hydroxyl and/or carboxyl groups by 50 mole percent or more, 70 mole percent or more, or 90 mole percent or more. The one or more functional compounds and/or pro-promoter siloxane compounds and/or reactive siloxane compounds can reduce the amount of free hydroxyl and/or carboxyl groups by 95 mole percent or more, 98 mole percent or more, or 99 mole percent or more. The molar amount of hydroxyl and/or carboxyl groups present in the recovery solution can be reduced by the molar amount of groups in the functional compounds and/or pro-promoter siloxane compounds and/or reactive siloxane compounds that are configured to react with hydroxyl and/or carboxyl groups.

After the siloxane-modified polycarbonate is formed, the recovered solution may be subjected to steps for recovering and/or separating the polycarbonate solvent and/or the siloxane-modified polycarbonate. The polycarbonate solvent and the siloxane-modified polycarbonate may be removed in a simultaneous manner or removed separately in sequence. The recovered solution may be subjected to process steps for simultaneously separating the polycarbonate solvent and the siloxane-modified polycarbonate so that the siloxane-modified polycarbonate may be used in downstream processes and the polycarbonate solvent may be reused to recover additional waste polycarbonate via a recycling route. The recovered solution may be subjected to any technique sufficient to separate the two components in a liquid state. The recovery solution may be subjected to one or more of devolatilization, centrifugation, filtration, distillation, or any combination thereof to separate the siloxane-modified polycarbonate and the polycarbonate solvent. The compounds remaining after the polycarbonate solvent and the siloxane-modified polycarbonate are removed may be discarded or subjected to further separation steps to recover the desired compounds and recycle them. A non-solvent may be contacted with the recovery solution to precipitate a form of the siloxane-modified polycarbonate from the polycarbonate solvent, the siloxane-modified polycarbonate being free or substantially free of impurities or being subjected to further separation techniques. The non-solvent may include one or more compounds that are immiscible with the polycarbonate solvent, such as water, aliphatic hydrocarbons, alcohols, acetonitrile, acetone, or any combination thereof.

The polycarbonate solvent can be recycled into new and untreated waste feedstock to recover additional waste polycarbonate, restart the process, and avoid improper disposal or loss of polycarbonate solvent. The polycarbonate solvent can be separated from the recovered solution and moved back to the storage or waste feedstock via one or more recycling paths extending between chambers. Before recycling back into contact with the waste feedstock, the polycarbonate solvent can be subjected to one or more separation steps to remove undesirable impurities. The polycarbonate solvent can be subjected to drying, centrifugal separation, filtration, distillation, or any combination thereof.

Prior to contacting the waste feedstock (including one or more reactive polycarbonates) and one or more polycarbonate solvents or solvent systems, the waste feedstock may be subjected to one or more pre-treatment steps to separate one or more non-polycarbonate compounds from the waste feedstock to recover the desired compound and/or to avoid undesirable reactions in the recycled feedstock. The waste feedstock may be subjected to any pre-treatment step configured to remove one or more non-polycarbonate compounds or to prepare the waste feedstock for more efficient extraction of the waste polycarbonate. The waste feedstock may be structurally altered to expose surface areas of components in the waste feedstock and/or to prepare the waste feedstock for downstream processing steps, which may be performed by shredding, grinding, pressing, decomposing, picking, or any combination thereof. The waste material may be treated to remove one or more non-polycarbonate compounds, such as inorganic compounds, non-polycarbonate polymers (e.g., polystyrene, styrene acrylonitrile, acrylonitrile butadiene styrene, high impact polystyrene, polymethyl methacrylate, other polymers typically blended with polycarbonate, etc.), organic small molecules, or any combination thereof. The waste material in the pre-treatment step may be subjected to melting, magnetic field, density separation, freezing, agglomeration, washing, chemical removal of binders, selective dissolution of other polymers, drying, heating, cooling, or any combination thereof.

The above steps can be done in the same chamber or in a series of chambers. Contacting the polycarbonate solvent and waste materials can be done in a first chamber; contacting the recovery solution and one or more functional compounds and/or precursor siloxane compounds and/or reactive siloxane compounds can be done in a second chamber, and recovery and/or separation of the polycarbonate solvent and siloxane-modified polycarbonate can be done in a third chamber. Performing the above steps in a series of chambers can reduce side reactions when adding functional compounds or reactive/precursor siloxane compounds, or more closely control the separation step. All steps can be performed in the same chamber in a single-pot, single-pot recovery, conditioning/repairing/modification and removal of polycarbonate in one location. One or more paths can separate the chambers and optionally move recovery solution, waste materials, polycarbonate solvent, siloxane-modified polycarbonate, or a combination thereof between chambers.

Between each of the above process steps, each of the chambers within the housing may be connected by paths configured to move compounds, such as recovery solution, waste feedstock, siloxane-modified polycarbonate, and/or polycarbonate solvent, between the chambers. The paths may include any equipment sufficient to move the compounds and/or provide additional processing. The paths may include equipment, such as filters, for separating one or more solid compounds from the recovery solution. The housing may include any number of paths between chambers. The housing may include one or more, two or more, three or more, four or more, or a plurality of paths between chambers. Each of the pathways may be configured to simply move compounds between chambers, recirculate polycarbonate solvent after processing polycarbonate, separate non-polycarbonate compounds from polycarbonate compounds, move separated non-polycarbonate compounds out of the enclosure, move waste materials into and out of the enclosure, or any combination thereof. The pathways or chambers may be equipped with equipment configured to monitor the concentration or properties of compounds present in the pathway or chamber. The pathways and/or chambers may be equipped with concentration sensors, number and/or weight average molecular weight sensors, impurity sensors, phase sensors for detecting solids, gases, or liquids, humidity sensors, temperature sensors, or any combination thereof.

The disclosed siloxane-modified polycarbonate compositions can be used to prepare structures comprising or containing the compositions using any known process such as extrusion, molding, thermoforming, and the like. The disclosed siloxane-modified polycarbonate compositions can be molded using procedures known in the art. The polycarbonate compositions can be molded into useful shaped articles by a variety of means such as injection molding, overmolding, extrusion, rotational molding, blow molding, and thermoforming to form a variety of shaped articles. Such articles may include: thin-walled consumer articles such as cell phones, MP3 players, computers, laptops, cameras, video recorders, electronic tablets, handheld receivers, kitchen appliances, appliance housings, etc. (e.g., smart meter housings and the like); electrical connectors, and assemblies for lighting fixtures, decorative articles, home appliances, roofs, greenhouses, sunrooms, swimming pool wraps, light-emitting diodes (LEDs) and light panels, extruded film and sheet articles; electrical components such as relays; and telecommunications components such as those used in base station terminals. The present disclosure further contemplates additional manufacturing operations for such articles, such as, but not limited to, molding, in-mold decoration, baking in a paint oven, lamination, and/or thermoforming. The disclosed composition is heated to a temperature at which the composition flows, which temperature may be above the glass transition temperature of the polycarbonate in the composition. The glass transition temperature is determined using differential scanning calorimetry. Such temperatures may be above 155°C, above 200°C or more, 250°C or more. Such temperatures may be 400°C or less or 300°C or less. The mold may be heated to facilitate processing, such as to 60°C or more, 80°C or more, or 100°C or more. Illustrative Examples Example 1. A method comprising: a. contacting one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups with one or more reactive siloxane compounds terminated by one or more methoxy, ethoxy, acetyloxy, halogenide and/or hydrogen groups in a solvent system to form one or more siloxane-modified polycarbonates in a recovery solution, wherein the one or more reactive polycarbonates include one or more waste polycarbonates. Example 2. The method of Example 1, wherein the one or more reactive polycarbonates include the one or more waste polycarbonates in an amount of about 5 weight percent to about 95 weight percent based on the total amount of the reactive polycarbonates. Embodiment 3. The method of Embodiment 1 or 2, wherein the free hydroxyl and/or carboxyl groups are located at one or more ends of the reactive polycarbonate. Embodiment 4. The method of Embodiment 3, wherein the free hydroxyl and/or carboxyl groups are located along the backbone of the reactive polycarbonate. Embodiment 5. The method of any of the foregoing embodiments, wherein the siloxane-modified polycarbonates have a number and/or weight average molecular weight that is at least 5 percent greater than the number and/or weight average molecular weight of the reactive polycarbonates incorporated into the siloxane-modified polycarbonate. Embodiment 6. The method of any of the preceding embodiments, further comprising: a. contacting the solvent system and one or more waste raw materials comprising the one or more waste polycarbonates and one or more non-polycarbonate compounds to form the recovery solution; and b. separating at least some of the one or more non-polycarbonate compounds from the recovery solution. Embodiment 7. The method of any of the preceding embodiments, further comprising: a. contacting one or more precursor siloxane compounds with water to form the one or more reactive siloxane compounds in the recovery solution; and b. contacting the recovery solution with one or more polycarbonate solvents to form the solvent system comprising the water and the one or more polycarbonate solvents in the recovery solution. Embodiment 8. The method of any of the preceding embodiments, further comprising: a. contacting the one or more reactive polycarbonates with one or more allyl halides to form one or more vinyl ether terminated polycarbonates, the one or more vinyl ether terminated polycarbonates being configured to react with the hydrogen atoms of the one or more reactive siloxane compounds and form the one or more siloxane modified polycarbonates. Embodiment 9. The method of any of the preceding embodiments, wherein the one or more allyl halides are terminated by an olefin and a halide and comprise between one and one hundred carbon atoms between the carbons at the halide and the olefin. Embodiment 10. The method of any of the preceding embodiments, further comprising: a. applying agitation to the recovery solution to mix the solvent system when the one or more reactive siloxane compounds or the one or more siloxane-modified polycarbonates are formed. Embodiment 11. The method of any of the preceding embodiments, further comprising: a. contacting the recovery solution with one or more scavengers to scavenge the acid formed by contacting the one or more reactive polycarbonates and the one or more reactive siloxane compounds. Embodiment 12. The method of any of the preceding embodiments, wherein the one or more scavengers comprise an alkaline wash, an adsorbent, or any combination thereof. Embodiment 13. The method of any of the preceding embodiments, wherein the reactive polycarbonate and the reactive siloxane compound are contacted in the presence of a catalyst configured to promote the formation of the siloxane-modified polycarbonate. Embodiment 14. The method of any of the preceding embodiments, further comprising: a. separating substantially all of the water from the recovered solution and the solvent system. Embodiment 15. The method of any of the preceding embodiments, wherein the step of separating the one or more non-polycarbonate compounds or the water from the recovered solution comprises filtration, decantation, centrifugation, extraction, or any combination thereof. Embodiment 16. The method of any of the preceding embodiments, wherein the solvent system comprises at least a polycarbonate solvent configured to dissolve the one or more reactive polycarbonates. Embodiment 17. The method of any of the preceding embodiments, wherein the solvent system further comprises water. Embodiment 18. The method of any of the preceding embodiments, wherein the siloxane-modified polycarbonate comprises one or more branched siloxane-polycarbonate copolymers. Embodiment 19. The method of any of the preceding embodiments, wherein the one or more reactive siloxane compounds comprise between one and one hundred siloxane units linked into chains terminated by at least one methoxy, ethoxy, acetoxy, halide and/or hydrogen group. Embodiment 20. The method of any of the preceding embodiments, wherein the one or more precursor siloxane compounds comprise at least two halide atoms at different ends. Embodiment 21. The method of any of the preceding embodiments, wherein the one or more precursor siloxane compounds comprise monohalogenated silanes, dihalogenated silanes, trihalogenated silanes and/or tetrahalogenated silanes. Embodiment 22. A polymerizable composition comprising: a. one or more reactive polycarbonates, the one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups along the main chain of the one or more reactive polycarbonates and/or at one or more ends of the one or more reactive polycarbonates, wherein the one or more reactive polycarbonates comprise one or more waste polycarbonates; b. a solvent system comprising one or more polycarbonate solvents and/or water; and c. one or more siloxane modifiers comprising at least one of the following: ⅰ one or more reactive siloxane compounds terminated by at least one hydrogen and one or more allyl halides; ⅱ One or more reactive siloxane compounds terminated by at least one methoxy, acetyloxy, ethoxy and/or halide group; or iii one or more precursor siloxane compounds configured to form in water one or more reactive siloxane compounds terminated by at least one halide, wherein the one or more reactive polycarbonates and the siloxane modifier are capable of reacting in the solvent system to form one or more siloxane-modified polycarbonates. Example 23. The polymerizable composition of Example 22, further comprising: a. one or more hydroxyl and/or carboxyl-containing compounds. Embodiment 24. The polymerizable composition of Embodiments 22 to 23, further comprising: a. One or more catalysts configured to promote the formation of siloxane-modified polycarbonates. Embodiment 25. The polymerizable composition of Embodiments 22 to 24, wherein the reactive polycarbonates further comprise one or more pristine polycarbonates. Example 26. A polymer composition comprising: a. One or more siloxane-modified polycarbonates comprising one or more of the following: i. one or more polycarbonate segments; and ii. one or more siloxane segments, the one or more siloxane segments being linked to the one or more polycarbonate segments at oxygen atoms along the backbone of the one or more polycarbonate segments and at the ends of the one or more polycarbonate segments, wherein at least some of the one or more siloxane segments link two or more polycarbonate segments. Example 27. A polymer composition as in Example 26, wherein the one or more siloxane-modified polycarbonates comprise one or more branched siloxane-polycarbonate copolymers. Example 28. The polymer composition of Examples 26 to 28, wherein the one or more polycarbonate chain segments contain dead polycarbonate residues. Example 29. The polymer composition of Examples 26 to 29, wherein the one or more polycarbonate chain segments at least include about 5 to 100 weight percent or more of dead polycarbonate residues based on the total amount of the siloxane-modified polycarbonate. Example 30. The polymer composition of Examples 26 to 30, wherein each of the one or more siloxane chain segments contains between two and 100 siloxane repeating units. Example 31. The polymer composition of Examples 26 to 31, wherein the polymer composition is substantially free of hydroxyl and/or carboxyl-containing compounds. Example 1:

The degraded polycarbonate (see Table 1, 10 g) was dissolved in 40 mL of dichloromethane and 0.25 mL of triethylamine was added, followed by 1,2-bis(chlorodimethylsilyl)ethane (180 mg). The reaction mixture was stirred at room temperature for 10 hours. Before work-up, a small sample was taken for analysis. The solution was washed twice with 0.1 M HCl solution and three times with demineralized water. After evaporation of the solvent, the siloxane-modified polycarbonate was obtained.

Table 1: Molecular weight distribution of degraded polycarbonate measured by size exclusion analysis and after treatment with 1,2-bis(chlorodimethylsilyl)ethane. Degradation of PC Processed PC (before finishing) Processed PC (after sorting) PD 2.10 2.16 2.20 Mn (Da) 7400 10400 11300 Mw (Da) 15500 22300 24800 Example 2:

The material produced in Example 1 was heated to 300°C in a melt flow rate apparatus and samples were taken after 0, 1, 2 and 5 minutes. GPC analysis showed no significant decrease in molecular weight, confirming high thermal stability.

Figure 1: GPC analysis of the data after heating the material to 300°C.

Table 2 shows the values for each minute of GPC analysis. time D Mn M Mz 0 minutes 2.21 11100 24700 37700 1 minute 2.23 10900 24400 37200 2 minutes 2.23 10900 24300 37200 5 minutes 2.20 10700 23600 36100 Example 3: Comparison with Example A

The PC-containing waste was dissolved in dichloromethane to obtain a 15 wt% solution. The insoluble portion was removed by coarse filtration with a 100 µm mesh filter cloth followed by fine filtration with a 0.6 µm cartridge. After removal of the solvent and drying of the recycled PC, the amount of free phenolic substances was determined (Table 3). Unless otherwise stated, phenolic substances were determined by those techniques described in connection with the hydroxyl and/or carboxyl containing compounds described herein and were measured and expressed in ppm. Example A

The PC-containing waste was dissolved in dichloromethane and filtered in a manner similar to that described in Comparative Example A. Then, 1,2-bis(chlorodimethylsilyl)ethane (0.28 wt%) was added together with triethylamine (0.27 wt%). After stirring, the solution was stirred for 12 hours and the organic part was washed with dilute hydrochloric acid solution (0.1 M) and water. The organic part was separated and the solvent was evaporated to obtain polycarbonate. After drying, the free phenolic substances were determined (Table 3). Unless otherwise stated, phenolic substances were determined by those techniques described in connection with the hydroxyl and/or carboxyl containing compounds described herein and were measured and expressed in ppm. Example B

The PC-containing waste was dissolved in dichloromethane and filtered in a manner similar to that described in Comparative Example 3. Then, 1,3-dichloro-1,1,3,3-tetramethyldisiloxane (0.27 wt%) was added together with triethylamine (0.27 wt%). After stirring, the solution was stirred for 12 hours, and the organic part was washed with dilute hydrochloric acid solution (0.1 M) and water. The organic part was separated, and the solvent was evaporated to obtain polycarbonate. After drying, the free phenolic substances were determined (Table 3). Unless otherwise stated, phenolic substances were determined by those techniques described in connection with the hydroxyl and/or carboxyl containing compounds described herein and were measured and expressed in ppm. Table 3 Comparison Example A Example A Example B 4-Butylphenol 118 5 4 Bisphenol-A 241 2 1 phenol twenty one 4 2

without

Figure 1 shows the GPC analysis of the data after heating the material to 300°C.

Claims (15)

A method comprising: a. contacting one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups with one or more reactive siloxane compounds terminated with one or more acetyloxy, methoxy, ethoxy, halide or hydrogen atoms in a solvent system to form one or more siloxane-modified polycarbonates in a recovery solution, wherein the one or more reactive polycarbonates comprise one or more waste polycarbonates. The method of claim 1, wherein the one or more reactive polycarbonates comprises the one or more waste polycarbonates in an amount of about 5 weight percent to about 95 weight percent based on the total amount of the reactive polycarbonates. The method of claim 1, wherein the free hydroxyl and/or carboxyl groups are located at one or more ends of the reactive polycarbonate. The method of claim 3, wherein the free hydroxyl groups and/or carboxyl groups are positioned along the backbone of the reactive polycarbonate. The method of claim 1, wherein the siloxane-modified polycarbonates have a number and/or weight average molecular weight that is at least 5 percent greater than the number and/or weight average molecular weight of the reactive polycarbonates incorporated into the siloxane-modified polycarbonate. The method of claim 1, further comprising: a. contacting one or more precursor siloxane compounds with water to form the one or more reactive siloxane compounds in the recovery solution; and b. contacting the recovery solution with one or more polycarbonate solvents to form the solvent system comprising the water and the one or more polycarbonate solvents in the recovery solution. The method of claim 1, further comprising: a. contacting the one or more reactive polycarbonates with one or more allyl halides to form one or more vinyl ether terminated polycarbonates, the one or more vinyl ether terminated polycarbonates being configured to react with the hydrogen atoms of the one or more reactive siloxane compounds and form the one or more siloxane modified polycarbonates, and wherein the one or more allyl halides are terminated by olefins and halides and contain between one and one hundred carbon atoms between the carbons at the halides and the olefins. The method of claim 1, further comprising: a. contacting one or more scavengers with the recovery solution to remove the acid formed by contacting the one or more reactive polycarbonates and the one or more reactive siloxane compounds, wherein the one or more scavengers comprise an alkaline wash solution, an adsorbent, or any combination thereof. The method of claim 1, wherein the solvent system comprises at least a polycarbonate solvent configured to dissolve the one or more reactive polycarbonates. A polymerizable composition comprising: a. one or more reactive polycarbonates, the one or more reactive polycarbonates having free hydroxyl and/or carboxyl groups along the backbone of the one or more reactive polycarbonates and/or at one or more ends of the one or more reactive polycarbonates, wherein the one or more reactive polycarbonates comprise one or more waste polycarbonates; b. a solvent system comprising one or more polycarbonate solvents and/or water; and c. one or more siloxane modifiers comprising at least one of the following: i. one or more reactive siloxane compounds terminated by at least one hydrogen and one or more allyl halides; ii. One or more reactive siloxane compounds terminated by at least one acetyloxy group, methoxy group, ethoxy group, halide or any combination thereof; or iii. One or more precursor siloxane compounds configured to form in water one or more reactive siloxane compounds terminated by at least one halide, wherein the one or more reactive polycarbonates and the siloxane modifier are capable of reacting in the solvent system to form one or more siloxane-modified polycarbonates. The polymerizable composition of claim 10 further comprises: a. One or more hydroxyl and/or carboxyl-containing compounds. A polymer composition comprising: a. One or more siloxane-modified polycarbonates comprising one or more of the following: i. One or more polycarbonate segments; and ii. One or more siloxane segments, the one or more siloxane segments being linked to the one or more polycarbonate segments at oxygen atoms along the backbone of the one or more polycarbonate segments and at the ends of the one or more polycarbonate segments, wherein at least some of the one or more siloxane segments are linked to two or more polycarbonate segments. A polymer composition as claimed in claim 12, wherein the one or more siloxane-modified polycarbonates comprise one or more branched siloxane-polycarbonate copolymers. A polymer composition as claimed in claim 12, wherein the one or more polycarbonate chain segments include at least about 5 to 100 weight percent or more of abandoned polycarbonate residues based on the total amount of the siloxane-modified polycarbonate. A polymer composition as claimed in claim 12, wherein the polymer composition is substantially free of hydroxyl and/or carboxyl containing compounds.