CN117004007A - Crystalline aliphatic polycarbonate with high molecular weight and high mechanical property and preparation method thereof - Google Patents

Abstract

The invention discloses a crystalline aliphatic polycarbonate with high molecular weight and high mechanical property and a preparation method thereof, belonging to the field of polymer synthesis, wherein the preparation method comprises the following steps: under the condition of solvent or bulk melting, a Lewis pair consisting of Lewis acid and Lewis base is used as a catalyst, an alcohol micromolecule is used as an initiator, and a monomer 1, 3-dioxacyclohepta-2-one is subjected to ring opening polymerization reaction, and after the polymerization reaction is completed, precipitation is carried out to obtain the polycarbonate. Compared with the condensation polymerization method commonly used at present, the polymerization method provided by the invention does not need high temperature and high pressure to remove small molecular byproducts, has relatively mild reaction conditions, better controllability and higher polymer molecular weight, can obtain crystalline polycarbonate with high molecular weight, high elongation at break and high mechanical strength, and has important significance in realizing high performance of polycarbonate and widening the application range of degradable polycarbonate materials.

Description

A kind of crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties and its preparation Preparation method

Technical field

The invention belongs to the technical field of polymer material synthesis, and in particular relates to a crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties and a preparation method thereof.

Background technique

Aliphatic polycarbonate has good biodegradability and biocompatibility and has important applications in film materials, elastomers, biomedicine, adhesives and other fields. High-pressure ring-opening copolymerization of _CO2 and alkylene oxide is an important method for the synthesis of aliphatic polycarbonate, and has been successfully used in the industrial production of polypropylene carbonate (PPC) and polycyclohexene carbonate (PCHC). However, epoxy compounds suitable for copolymerization with _CO2 are limited to three-membered and four-membered epoxy compounds with large ring tension. There are fewer types of monomers, resulting in a relatively single product structure and performance. At the same time, during the copolymerization process, side reactions such as homopolymerization of alkylene oxide and the formation of small molecule cyclic carbonates are prone to occur. In addition, the resulting products PPC and PCHC are usually amorphous polymers with poor mechanical properties.

The thermal and mechanical properties of polycarbonate depend on its chain structure. Increasing the number of consecutive methylene groups between two adjacent carbonate groups can transform polycarbonate from amorphous to crystalline polymer. For example: polyethylene carbonate and polytrimethylene carbonate with two carbonate groups of 2 and 3 carbon atoms respectively are amorphous polymers with poor mechanical properties; when two adjacent carbonate groups When the number of methylene groups in the polymer increases to 4, the poly(1,4-butylene carbonate) polymer exhibits crystallinity. Due to the existence of the crystalline structure, poly(1,4-butylene carbonate) maintains flexibility while also exhibiting high tensile strength, further broadening the application range of polycarbonate.

Poly(1,4-butylene carbonate) and crystalline polycarbonate containing more methylene units cannot be synthesized by high-pressure copolymerization of _CO2 , tetrahydrofuran and macrocyclic ethers. The main reason is that tetrahydrofuran and macrocyclic epoxy The ring tension of the compound is small, making it difficult to carry out coordination anionic polymerization. Therefore, the current main method for synthesizing crystalline polycarbonate is the transesterification-polycondensation reaction of dialkyl carbonate and α,ω-diol. This method has poor control over the structure and molecular weight of the polymer. At the same time, since the transesterification method requires reaction under harsh conditions such as high temperature and high vacuum, the polymerization process is usually accompanied by many side reactions. For example: the chain end bites back to form cyclic low molecular weight polycarbonate; 1,4-butanediol is dehydrated to form tetrahydrofuran, etc. (Reference: Lee BY et al, Macromolecules 2013, 46, 3301-330). Patent CN200810117766.2 discloses a method for preparing crystalline polycarbonate by transesterification-polycondensation reaction of glycol/dialkyl carbonate under high temperature conditions. The number average molecular weight range of the polycarbonate obtained by the transesterification-polycondensation method is only 6,000 to 20,000 kDa, which is relatively low; and the patent does not involve information on the thermal properties and mechanical properties of the polycarbonate.

Crystalline polycarbonate can also be prepared by reacting carbon dioxide and glycol in the presence of catalysts and dehydrating agents. For example: Tomishige, K. et al. reported that carbon dioxide and long-chain glycol can prepare polycarbonate in the presence of cerium dioxide (catalyst) and furancarbonitrile (dehydrating agent) (Reference: ACS Sustainable Chem.Eng.2019,7 ,6304-6315). This method not only requires the use of a large amount of expensive furan and carbonitrile, but also the number average molecular weight (M _n ) of the prepared polycarbonate is only 5000kDa at most. At such a low molecular weight, polycarbonate has almost no mechanical strength and is difficult to use as a material.

Polycarbonate can also be prepared by ring-opening polymerization of cyclic carbonate monomers under the action of a catalyst. Compared with the previous three methods, this method not only has mild polymerization reaction conditions and controllable polymer structure, but also has a wide range of substrates that can be used, making it easy to control the polymer structure and properties. It is the best way to prepare polycarbonate with a clear structure. Optimal method. The most representative example is the preparation of amorphous poly(trimethylene carbonate) from the ring-opening polymerization of 6-membered ring monomer trimethylene carbonate (J.Chem.Educ.2015,92,708-713). Zhu J. et al. reported a method for preparing high molecular weight polycarbonate by ring-opening polymerization of substituted 1,3-dioxepan-2-one. Despite the higher molecular weight of these polycarbonates, the polymers are still amorphous (ACS Macro Lett. 2022, 11, 2, 173-178). Subsequently, Zhu J. et al. reported a type of crystalline polycarbonate containing rigid cyclic units in the main chain. Although this type of polycarbonate is crystalline, the elongation at break of these polycarbonates does not exceed 300% due to rigid cyclic substituents that increase the brittleness and reduce the flexibility of the polymer (Macromolecules 2022,55 ,9232-9241). Buchard A. et al. reported a method for preparing crystalline polycarbonate containing unsaturated double bonds in the main chain through ring-opening polymerization of 1,3-dioxepan-2-one derivatives. Since this method uses an organic base as a catalyst, transesterification side reactions are prone to occur during the polymerization process, resulting in a low molecular weight of the polymer, with a maximum number average molecular weight of only 20 kDa. At the same time, relevant information such as the mechanical properties of polycarbonate is not disclosed in the literature (J.Am.Chem.Soc.2019, 141, 13301-13305).

From the above analysis, it can be seen that in the field of polycarbonate synthesis, there are still great challenges in preparing crystalline aliphatic polycarbonate with high molecular weight, high elongation at break and high mechanical strength through ring-opening polymerization. The high molecular weight, high elongation at break and high mechanical strength enable polycarbonate to have a wider range of applications. Therefore, it is very necessary to provide a synthesis method of polycarbonate with high molecular weight, high elongation at break and high mechanical strength to promote the development of high-performance polycarbonate.

Contents of the invention

The purpose of the present invention is to provide a crystalline aliphatic polycarbonate with high molecular weight, high elongation at break and high mechanical strength and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art and realize the high performance of polycarbonate. to promote the development of degradable polycarbonate materials.

In order to achieve the above object, the present invention provides a method for preparing crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties, which includes the following steps: using Lewis acid (Lewis acid) and Lewis acid under solvent or bulk melting conditions. A Lewis acid-base pair composed of a Lewis base is used as a catalyst, and a small molecular alcohol is used as an initiator to perform a ring-opening polymerization reaction on the monomer 1,3-dioxepan-2-one. After the polymerization reaction is completed, it is precipitated to obtain the crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties.

The invention provides a method for preparing crystalline aliphatic polycarbonate with high molecular weight, high elongation at break and high mechanical strength by ring-opening polymerization of seven-membered ring carbonate monomer. The reaction formula is as shown in Formula I:

Further, the molar ratio of Lewis acid and Lewis base in the Lewis pair is 1:1.

Further, the Lewis acid is diethyl zinc (ZnEt ₂ ), diphenyl zinc (Zn (C ₆ H ₅ ) ₂ ), dipentafluorophenyl zinc (Zn (C ₆ F ₅ ) ₂ ), tris One of methylaluminum (AlMe ₃ ) and triisobutylaluminum (Al ⁱ Bu ₃ );

The Lewis base is dimethylpyridine (DMAP), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4. One of 0]dec-5-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD).

Further, the small molecular alcohols are benzyl alcohol, terephthalyl alcohol or butylene glycol.

Further, the solvent is dichloromethane, tetrahydrofuran or toluene, and the concentration is 0.5-5 mol/L.

Further, the molar ratio of the catalyst, initiator and monomer is 1:1: (500-50000).

Further, the temperature of the ring-opening polymerization reaction is 25 to 120°C, and the time is 1 to 720 minutes.

Further, the precipitating agent used for precipitation is ethanol or n-hexane.

Furthermore, the steps of filtration and drying are also included after precipitation.

A crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties is prepared according to the above preparation method. It is a crystalline polymer with a number average molecular weight of 60,000 to 600,000 Da, a molecular weight distribution of 1.2 to 1.6, and a melting temperature of 51 ~58℃.

Further, the crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties has a yield strength of 6 to 7 MPa, an elongation at break of 480 to 800%, and a breaking strength of 14 to 25 MPa.

The crystalline aliphatic polycarbonate with high molecular weight and high mechanical properties is used in the fields of film materials, elastomers, biomedical materials and adhesives.

Compared with the existing technology, the present invention has the following advantages and technical effects:

Compared with the condensation polymerization method commonly used in the synthesis of poly(1,4-butylene carbonate), the polymerization method provided by the present invention does not require high temperature and high pressure to exclude small molecule by-products. The reaction conditions are relatively mild and the controllability is better. The polymer molecular weight is higher. The present invention uses a Lewis pair composed of Lewis acid and Lewis base as a catalyst. The Lewis acid/base synergistic effect can effectively suppress the transesterification side reaction of the polymerization reaction and easily prepare high molecular weight polycarbonate materials. The preparation method of the present invention can make the conversion rate of 1,3-dioxepan-2-one monomer reach up to 100%, and the obtained poly(1,4-butylene carbonate) has a clear structure and a carbonate content of > 99%, the number average molecular weight of polycarbonate is 60000~600000Da, and the molecular weight distribution is 1.2~1.6. The polycarbonate obtained by the present invention is a crystalline polymer with a melting temperature of 51 to 58°C. The obtained polycarbonate exhibits excellent mechanical properties, with a yield strength of 6 to 7 MPa, an elongation at break of 480 to 800%, and a breaking strength of 14 to 25 MPa.

The ring-opening polymerization of 1,3-dioxepan-2-one provided by the invention prepares crystalline polycarbonate with high molecular weight, high elongation at break and high mechanical strength, which can realize high performance of polycarbonate and broaden its potential. The range of applications of degradable polycarbonate materials is of great significance.

Description of the drawings

The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached picture:

Figure 1 is a ¹ H NMR spectrum of poly(1,4-butanediol carbonate) prepared in Example 2 of the present invention;

Figure 2 is a DSC curve of poly(1,4-butanediol carbonate) prepared in Example 11 of the present invention;

Figure 3 is the stress strain curve of poly(1,4-butylene carbonate) prepared in Example 11 of the present invention;

Figure 4 is a DSC curve of poly(1,4-butanediol carbonate) prepared in Example 12 of the present invention;

Figure 5 is the stress strain curve of poly(1,4-butylene carbonate) prepared in Example 12 of the present invention;

Figure 6 is the stress strain curve of poly(1,4-butylene carbonate) prepared in Example 13 of the present invention;

Figure 7 is a DSC curve of poly(1,4-butylene carbonate) prepared in Example 14 of the present invention.

Detailed ways

Various exemplary embodiments of the invention will now be described in detail. This detailed description should not be construed as limitations of the invention, but rather as a more detailed description of certain aspects, features and embodiments of the invention.

It should be understood that the terms used in the present invention are only used to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges in the present invention, it should be understood that every intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or value intermediate within a stated range, and any other stated value or value intermediate within a stated range, is also included within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials in connection with which the documents relate. In the event of conflict with any incorporated document, the contents of this specification shall prevail.

It will be apparent to those skilled in the art that various modifications and changes can be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to the skilled person from the description of the invention. The specification and examples of the present invention are exemplary only.

The words "includes", "includes", "has", "contains", etc. used in this article are all open terms, which mean including but not limited to.

Unless otherwise specified, the room temperature in the embodiments of the present invention refers to 25±2°C.

In the present invention, a Lewis pair composed of Lewis acid and Lewis base is used as a catalyst, and hexanol small molecules are used as initiators. The monomer 1,3-dioxepan-2-one is ring-opened under solvent or bulk melting conditions. Polymerization reaction. After the polymerization reaction is completed, precipitation is performed to obtain the polycarbonate. The reaction formula is as shown in formula (I):

The Lewis acid of the present invention is diethyl zinc (ZnEt ₂ ), diphenyl zinc (Zn (C ₆ H ₅ ) ₂ ), dipentafluorophenyl zinc (Zn (C ₆ F ₅ ) ₂ ), trimethyl One of the base aluminum (AlMe ₃ ) and triisobutylaluminum (Al ⁱ Bu ₃ ); the Lewis base is dimethylpyridine (DMAP), 1,8-diazabicyclo[5.4.0]undecane -7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 7-methyl-1,5,7-triazabicyclo[4.4 .0] One of dec-5-ene (MTBD); the Lewis pair is an equimolar combination of any of the above-mentioned Lewis acids and any of the Lewis bases.

During the preparation of aliphatic polycarbonate esters from the ring-opening polymerization of 1,3-dioxepan-2-one, all operations sensitive to moisture and oxygen are carried out by professionals familiar with the art in an MBraun glove box or Performed using standard Schlenk technique under nitrogen protection.

When performing relevant tests on the prepared polymers, nuclear magnetic resonance spectroscopy was used to determine the structure of the polymer, gel chromatography (GPC) was used to determine the molecular weight and molecular weight distribution index of the polymer, and differential scanning calorimeter was used to determine the thermal energy of the polymer. Properties, a universal tensile machine was used to determine the mechanical properties of the polymer. Among them, ^{the 1} H and ¹³ C NMR of the polymer were measured by a Bruker-400 nuclear magnetic resonance instrument at 25°C, TMS was the internal standard, and the solvent was deuterated chloroform; the gel chromatography was measured by a Waters gel permeation chromatograph: tetrahydrofuran ( THF) as the solvent (add 0.05wt% 2,6-di-tert-butyl-4-methylphenol as an antioxidant). The test temperature is 40°C, the flow rate is 1.0mL/min, and PL EasiCal PS-1 is used as the standard sample. ; The differential scanning calorimeter is measured by TA. First, the temperature is raised to 150.00°C at a rate of 5.000°C/min. After the temperature is held constant for 5.00min, the temperature is lowered at a rate of 5.000°C/min until -50.00°C. The temperature is then kept constant for 5.00min for the second time. heating; when measuring mechanical properties with a universal stretching machine, the polymer is first hot-pressed at 120°C into a sample piece, and then cut into a 5×10mm tensile spline with a stretching rate of 10mm/min.

Example 1

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and dimethylpyridine (DMAP).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and DMAP, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 720 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 60.4kDa, and the molecular weight distribution is 1.05; DSC analysis shows that the polymer T _m is 57.5°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 1 is 6.06MPa, and the elongation at break is 483%. , the breaking strength is 14.1MPa.

Example 2

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 480 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butylene carbonate) was subjected to nuclear magnetic analysis and GPC analysis: Figure 1 is the ¹ H NMR spectrum of the poly(1,4-butylene carbonate) prepared in Example 2. , the results show that the polycarbonate content of the polymer is >99%; the GPC analysis results show that the polymer molecular weight is 64.5kDa and the molecular weight distribution is 1.11; the DSC analysis shows that the polymer T _m is 57.1°C; the universal tensile machine test results show that the embodiment The yield strength of the polymer produced in 2 was 6.28MPa, the elongation at break was 511%, and the breaking strength was 14.8MPa.

Example 3

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL dichloromethane at room temperature. Ring-opening polymerization was carried out, and the polymerization reaction was carried out for 720 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 66.5kDa, and the molecular weight distribution is 1.12; DSC analysis shows that the polymer T _m is 57.4°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 3 is 6.02MPa, and the elongation at break is 487%. , the breaking strength is 14.2MPa.

Example 4

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene ( TBD).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and TBD, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 270 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 61.9kDa, and the molecular weight distribution is 1.29; DSC analysis shows that the polymer T _m is 57.4°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 4 is 5.98MPa, and the elongation at break is 485%. , the breaking strength is 14.3MPa.

Example 5

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 7-methyl-1,5,7-triazabicyclo [4.4.0] Dec-5-ene (MTBD).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and MTBD, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 240 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 72.2kDa, and the molecular weight distribution is 1.39; DSC analysis shows that the polymer T _m is 56.9°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 5 is 6.21MPa, and the elongation at break is 508%. , the breaking strength is 15.6MPa.

Example 6

The catalysts used in this example are commercially available zinc diethyl (ZnEt ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol ZnEt ₂ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, then add 20 mL dichloromethane, and keep at room temperature Carry out ring-opening polymerization and polymerize for 180 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 71.4kDa, and the molecular weight distribution is 1.59; DSC analysis shows that the polymer T _m is 57.1°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 6 is 6.32MPa, and the elongation at break is 519%. , the breaking strength is 15.4MPa.

Example 7

The catalysts used in this example are commercially available diphenylzinc (Zn(C ₆ H ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). .

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ H ₅ ) ₂ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 180 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 87.4kDa, and the molecular weight distribution is 1.10; DSC analysis shows that the polymer T _m is 56.5°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 7 is 6.39MPa, and the elongation at break is 525%. , the breaking strength is 16.5MPa.

Example 8

The catalysts used in this example are commercially available trimethylaluminum (AlMe ₃ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol AlMe ₃ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, then add 20 mL dichloromethane, and keep at room temperature. Carry out ring-opening polymerization and polymerize for 660 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 63.2kDa, and the molecular weight distribution is 1.55; DSC analysis shows that the polymer T _m is 57.6°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 8 is 6.17MPa, and the elongation at break is 500% , the breaking strength is 14.7MPa.

Example 9

The catalysts used in this example are commercially available triisobutylaluminum (Al ⁱ Bu ₃ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol ^Ali Bu ₃ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL dichloromethane. Ring-opening polymerization was performed at room temperature, and the polymerization reaction was carried out for 720 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 60.7kDa, and the molecular weight distribution is 1.35; DSC analysis shows that the polymer T _m is 57.5°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 9 is 6.05MPa, and the elongation at break is 495%. , the breaking strength is 14.5MPa.

Example 10

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Tetrahydrofuran, perform ring-opening polymerization at room temperature, and polymerize for 720 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 74.2kDa, and the molecular weight distribution is 1.11; DSC analysis shows that the polymer T _m is 57.2°C; the universal tensile machine test results show that the yield strength of the polymer prepared in Example 10 is 6.27MPa, and the elongation at break is 512%. , the breaking strength is 15.3MPa.

Example 11

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 10 μmol benzyl alcohol, 5000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 10 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 540 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the substance is 64.3kDa, and the molecular weight distribution is 1.12; Figure 2 is the DSC curve of the poly(1,4-butanediol carbonate) prepared in Example 11. The analysis results show that the T _m of the polymer is 57.1°C; Figure 3 This is the stress strain curve of the poly(1,4-butylene carbonate) prepared in Example 11. The universal tensile machine test results show that the yield strength of the polymer prepared in Example 11 is 6.10MPa, and the elongation at break is 490%, breaking strength is 14.4MPa.

Example 12

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 10 μmol benzyl alcohol, 10000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 480 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the substance is 122.4kDa, and the molecular weight distribution is 1.11; Figure 4 is the DSC curve of the poly(1,4-butanediol carbonate) prepared in Example 12. The analysis results show that the T _m of the polymer is 56.3°C; Figure 5 This is the stress strain curve of the poly(1,4-butylene carbonate) prepared in Example 12. The universal tensile machine test results show that the yield strength of the polymer prepared in Example 12 is 6.45MPa, and the elongation at break is 549%, breaking strength is 17.4MPa.

Example 13

The catalysts used in this example are commercially available diphenylzinc (Zn(C ₆ H ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). .

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 10 μmol Zn(C ₆ H ₅ ) ₂ and DBU, 10 μmol benzyl alcohol, 10000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 120 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the substance is 121.2kDa, and the molecular weight distribution is 1.54; DSC analysis shows that the T _{m of} the polymer is 55.2°C; Figure 6 is the stress strain curve of the poly(1,4-butylene carbonate) prepared in Example 13. The tensile test results show that the yield strength of the polymer produced in this example is 6.75MPa, the elongation at break is 574%, and the breaking strength is 17.2MPa.

Example 14

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 4 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 4 μmol benzyl alcohol, 10000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 720 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the substance is 206.5kDa, and the molecular weight distribution is 1.22; Figure 7 is the DSC curve of the poly(1,4-butylene carbonate) prepared in Example 14. The analysis results show that the _Tm of the polymer is 51.5°C; Wannengla The tensile test results show that the yield strength of the polymer produced in this example is 6.55MPa, the elongation at break is 664%, and the breaking strength is 19.6MPa.

Example 15

The catalysts used in this example are commercially available zinc dipentafluorophenyl (Zn(C ₆ F ₅ ) ₂ ) and 1,8-diazabicyclo[5.4.0]undec-7-ene ( DBU).

The preparation method includes the following steps:

(1) Under an inert atmosphere, add 4 μmol Zn(C ₆ F ₅ ) ₂ and DBU, 4 μmol benzyl alcohol, 50000 μmol 1,3-dioxepan-2-one into a dry 50 mL reaction kettle, and then add 20 mL Dichloromethane, perform ring-opening polymerization at room temperature, and polymerize for 720 minutes under stirring at 500 rpm;

(2) After the polymerization is completed, pour the reaction system in the kettle into 100 mL of methanol to settle, and then filter, wash, and vacuum dry to obtain poly(1,4-butanediol carbonate).

The conversion rate of 1,3-dioxepan-2-one monomer in this example is 100%.

The prepared poly(1,4-butanediol carbonate) was subjected to nuclear magnetic analysis, GPC analysis, DSC analysis and mechanical property testing: nuclear magnetic analysis showed that the polycarbonate content of the polymer was >99%; the GPC analysis results showed that the polymerization The molecular weight of the material is 596.5kDa, and the molecular weight distribution is 1.22; DSC analysis shows that the T _m of the polymer is 51.5°C; the universal tensile machine test results show that the yield strength of the polymer is 6.55MPa, the elongation at break is 800%, and the breaking strength is 25MPa .

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present invention. All are covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (10)

1. A method for preparing crystalline aliphatic polycarbonate with high molecular weight and high mechanical property, which is characterized by comprising the following steps: under the condition of solvent or bulk melting, a Lewis acid-base pair formed by Lewis acid and Lewis base is used as a catalyst, micromolecular alcohols are used as an initiator, the ring-opening polymerization reaction is carried out on monomer 1, 3-dioxacyclohepta-2-ketone, and after the ring-opening polymerization reaction is finished, the high molecular weight and high mechanical property crystalline aliphatic polycarbonate is obtained by precipitation.

2. The method for producing a crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 1, wherein the molar ratio of the lewis acid base to the lewis acid to the lewis base is 1:1.

3. The method for preparing a crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 2, wherein the lewis acid is one of diethyl zinc, diphenyl zinc, dipentafluorophenyl zinc, trimethylaluminum and triisobutylaluminum;

the Lewis base is one of lutidine, 1, 8-diazabicyclo [5.4.0] undec-7-ene and 1,5, 7-triazabicyclo [4.4.0] dec-5-ene, and 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene.

4. The method for producing a crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 1, wherein the small molecule alcohol is benzyl alcohol, terephthalyl alcohol or butanediol.

5. The method for producing a crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 1, wherein the solvent is methylene chloride, tetrahydrofuran or toluene.

6. The method for producing a crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 1, wherein the molar ratio of the catalyst, the initiator and the monomer is 1:1:500 to 50000.

7. The method for producing a crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 1, wherein the ring-opening polymerization reaction is carried out at a temperature of 25 to 120℃for a period of 1 to 720 minutes.

8. Crystalline aliphatic polycarbonate with high molecular weight and high mechanical property, which is characterized in that the crystalline aliphatic polycarbonate is prepared by the preparation method of claims 1-7, and is a crystalline polymer with number average molecular weight of 60000-600000 Da, molecular weight distribution of 1.2-1.6 and melting temperature of 51-58 ℃.

9. The crystalline aliphatic polycarbonate having a high molecular weight and high mechanical properties according to claim 8, wherein the yield strength is 6 to 7MPa, the elongation at break is 480 to 800% and the breaking strength is 14 to 25MPa.

10. Use of the crystalline aliphatic polycarbonate of high molecular weight and high mechanical properties according to claim 8 or 9 in the fields of film materials, elastomers, biomedical materials and adhesives.