CN1254493C - Process for preparing polyphenylacetylene / polyacrylacid ester self-expansion macromolecular alloy - Google Patents

Abstract

The invention provides a method for in-situ preparation of a polystyrene/polyacrylate self-compatibilizing polymer alloy. The method adopts a concentrated emulsion polymerization method, including prepolymerization and Addition of macromers in two stages of polymerization. The first stage: using styrene-based/acrylate monomers as research templates, first prepare a thick emulsion of the two, and then perform pre-polymerization; the second stage: partially pre-polymerized styrene-based and acrylate-based monomers The thick emulsion is mixed, and then the macromonomer is added, and the polymerization is continued until the reaction is completed, thereby obtaining a self-compatibilized polymer alloy.

Description

A kind of preparation method of polystyrene/polyacrylate self-compatibilizing polymer alloy

technical field

The invention relates to a preparation method of a self-compatibilizing polymer alloy, more specifically, the invention relates to a preparation method of a polystyrene/polyacrylate self-compatibilizing polymer alloy.

Background technique

Blending two or more polymers is the most convenient and effective way to obtain new materials. The blended polymer can have both the chemical and physical properties of the individual components, and often can produce properties that the individual components do not have, which produces the so-called synergistic effect. This synergistic effect is more likely to occur when the chemical nature of the blends differs greatly. Therefore, research on the blending of incompatible polymers has become the mainstream of polymer blending research in the past 20 years. However, the incompatibility between polymers will cause phase separation, and the components cannot be well dispersed, which will seriously affect the physical and mechanical properties. Therefore, the compatibilization of blends has increasingly become the focus of attention.

Adding compatibilizer is the most important method to improve compatibility. No. CN1198452 patent application discloses the method that olefin compound and methacrylate improve compatibility by adding block copolymer; No. CN1200384 patent discloses high-impact polyphenylene ether/styrene resin/elastomer composition by adding 2- 40% block copolymer improves the compatibility method; US6462131 patent discloses a kind of preparation method of isobutylene-alkyl styrene type block copolymer, uses isobutylene-alkyl styrene type block copolymer as The compatibilizer improves the compatibility between polyisobutylene and polystyrene. The disadvantage of adding a compatibilizer for compatibilization is that the compatibilizer is expensive, it is difficult to disperse the compatibilizer uniformly in the polymer matrix, the compatibilizing effect is poor, and the processing technology is complicated and the cost is high.

Reactive compatibilization is a common method to improve the compatibility between polymers in recent years. Reactive compatibilizers are mainly copolymers containing functional groups that can chemically react with blending components. US6469099 patent discloses a method for compatibilizing hydrocarbon and polyurethane blends. It is a compatibilized thermoplastic blend prepared by reacting functional groups on hydrocarbons with polyurethane. No. US6437049 patent discloses a method of grafting polypropylene with maleic anhydride to improve the compatibility of polypropylene blends. However, each of the above methods has its own limitations. The residence time of the material in the extruder is limited, the compatibilization reaction is difficult to fully proceed, and the compatibilization effect is poor. Heat is generated during the reaction at the same time, causing inconvenience to temperature control. Therefore, the above-mentioned capacity-increasing method is not an ideal way for some systems.

Contents of the invention

The purpose of this invention is to provide a kind of thick emulsion polymerization preparation method of polystyrene/polyacrylate self-compatibilizing macromolecule alloy, make the polymerization of styrene monomer or acrylate monomer and the synthesis of compatibilizer in the polymerization process The generation proceeds synchronously. After the polymerization is completed, the obtained blend polymer includes homopolymers of styrene-based monomers, homopolymers of acrylate-based monomers, and polymers of styrene-based monomers and acrylate-based monomers. Compatibilizer generated in situ at the homopolymer phase interface. The synthesis, blending and compatibilization of the polymer of the styrene monomer and the acrylate monomer are completed at one time, and the product obtained after the polymerization is a compatibilized polymer alloy.

The invention relates to a preparation method of polystyrene/polyacrylate self-compatibilizing polymer alloy, which adopts the method of thick emulsion polymerization, including prepolymerization of styrene-based and acrylate-based monomer thick emulsion and adding macromonomers The aggregation; the specific steps are as follows:

A: Prepare concentrated emulsions of styrene-based and acrylate-based monomers with a volume fraction of 75-89%, preferably 79%, and prepolymerize at 40-60°C respectively, until the conversion rate of monomers is 10-25% ;

B: Mix the prepolymerized styrene-based and acrylate-based monomer emulsions obtained in step A at a volume ratio of 1/4-4/1, add macromonomers and initiators, and the amount of macromolecules added It is 3.6-6.75% of the total monomer volume, preferably 6.75%. The addition amount of the initiator is 0.5% of the total mass of the monomers. The polymerization reaction is carried out at 40-80° C., preferably 60° C., and the reaction is terminated when the total conversion rate of the monomer reaches above 96%, and the product is collected.

The styrene-based monomers used in the present invention refer to styrene or styrene derivatives with C ₁ to C ₁₅ aliphatic substituents on the benzene ring; the molecular formula of the acrylate monomer is CH ₂ C (R ₁ )COOR ₂ , wherein R ₁ =H, CH ₃ ; R ₂ =C ₁ -C ₂₀ alkyl.

The macromonomer mentioned in the above step B is an oligomer having a polymerizable double bond at both ends, preferably polyethylene glycol diacrylate. The macromonomer can be added in the preparation of the monomer thick emulsion, or can be added after the prepolymerized thick emulsion is evenly mixed. Among them, it is the optimal solution to add the macromonomer after the partially polymerized concentrated emulsion is evenly mixed.

The initiator is an azo or organic peroxy initiator, preferably azobisisobutyronitrile or dibenzoyl peroxide.

The used tensio-active agent of preparation styrene system and acrylic acid ester monomer concentrated emulsion in the step A is anionic surfactant, preferably surfactant sodium lauryl sulfate or sodium lauryl sulfonate, and consumption is 1.0 - 8.0 g/100 ml _H2O .

In step B, the volume ratio of mixing the concentrated emulsion of styrene-based monomers and acrylate-based monomers after prepolymerization is preferably 3/2-2/3, preferably 1/1.

The polymerization reaction of the present invention can be carried out in conventional polymerization reactors and conventional reaction vessels. The process of preparing the polystyrene/polyacrylate polymer alloy includes two stages, the first stage: first prepare the thick emulsion of the styrene monomer and the acrylate monomer. In a concentrated emulsion system, the monomer acts as the dispersed phase and the water acts as the continuous phase. Then carry out the pre-polymerization respectively; the second stage: mix the concentrated emulsion of partially pre-polymerized styrene-based and acrylate-based monomers, add macromonomers to the mixed pre-polymerized concentrated emulsion system, and keep the same as the first stage Under the experimental conditions, the polymerization was continued until the end of the reaction. Utilizing the characteristic that the macromonomer exists between the droplets of the concentrated emulsion, it plays the role of crosslinking in the further polymerization process, thereby generating a micro-crosslinked copolymer between the droplets of different monomers. A self-compatibilized polystyrene/polyacrylate polymer alloy was prepared using a micro-crosslinked copolymer formed in situ at the droplet interface as a compatibilizer. After the polymerization is completed, the obtained polymerization product is powdery polymer particles.

The degree of polymerization reaction in the first stage should be controlled at a monomer conversion rate of 10-25%. The specific polymerization reaction time is related to the type of monomer, the amount of initiator, and the polymerization reaction temperature; the polymerization reaction time of the second stage The conversion rate of the monomer should be guaranteed to be above 96%, and the specific reaction time is related to the nature of the monomer, the amount of the initiator and the polymerization temperature.

The method of the present invention has distinctive features: (1) what is mixed is not the polymkeric substance of styrene-based monomer and acrylate monomer, but the thick emulsion droplet that has not yet completed polymerization; (2) partially polymerized styrene After mixing the thick emulsion and the thick emulsion of the acrylate, the styrene-based monomer or the acrylate-based monomer reacts with the macromonomer on the droplet interface to form a micro-crosslinked copolymer to realize the synthesis of the styrene-based monomer. Compatibilization between polymers and polymers of acrylate monomers; (3) The polymerization product is not a single polymer but a compatibilized blend. In the method of the present invention, the synthesis, blending and compatibilization of the two polymers are completed at one time, and the product obtained after the polymerization is a compatibilized blended polymer.

Should comprise the homopolymer (polystyrene and polyacrylate) of respective monomer in the polystyrene/polyacrylate macromolecule alloy of self-compatibilization prepared according to the present invention, macromonomer and styrenic monomer Slightly cross-linked copolymers produced from monomers and acrylate monomers, random copolymers of styrene monomers and acrylate monomers. Among them, it is generally believed that the micro-crosslinked copolymers formed by macromonomers, styrene-based monomers and acrylate-based monomers are generally considered to play a role in compatibilization.

The method of the invention can complete the polymerization and dispersion at one time, which not only simplifies the preparation process, but also makes the phase structure of the obtained polymer alloy evenly distributed, thereby ensuring that the product has higher physical and mechanical properties.

Description of drawings

Fig. 1 is the transmission electron micrograph of the product obtained in Example 1 of the present invention, and its magnification is 100,000 times;

Fig. 2 is the transmission electron micrograph of the product obtained in Example 2 of the present invention, and its magnification is 100,000 times;

Fig. 3 is the transmission electron micrograph of the product obtained in Example 3 of the present invention, and its magnification is 100,000 times;

Fig. 4 is the transmission electron micrograph of the product obtained in Example 4 of the present invention, and its magnification is 100,000 times;

Fig. 5 is the transmission electron micrograph of the product obtained in Example 5 of the present invention, and its magnification is 100,000 times;

As can be seen from the accompanying drawings, macromolecular monomers and styrene monomers and acrylate monomers in the polymer alloy product obtained by the present invention have formed micro-crosslinked copolymers, and the compatibility between polymers good.

Detailed ways

Example 1

Move 4ml of sodium lauryl sulfate aqueous solution (concentration is 0.08g/ml H ₂ O) into the 100mL flask with magnetic stirring bar, and under vigorous stirring conditions, add 15ml of dissolved initiator to the flask with a syringe The styrene monomer of azobisisobutyronitrile (0.5g/100g styrene), the process lasts for about 20min, after the dropwise addition is completed, continue to stir for 10min, so that the size of the latex particles in the dispersed phase in the emulsion system is uniform, and the emulsion is stabilized In the same way, move 1ml of sodium lauryl sulfate aqueous solution (concentration is 0.08g/ml H ₂ O) into the 100mL flask with magnetic stirring bar, under the condition of vigorous stirring, add dropwise in the flask with syringe 3.75ml is dissolved with the butyl acrylate monomer of initiator azobisisobutyronitrile (0.5g/100g butyl acrylate), prepares butyl acrylate thick emulsion, and the volume fraction of dispersed phase in two kinds of thick emulsions is 79 now %.

The concentrated emulsions of styrene and butyl acrylate were respectively transferred to a constant temperature water bath at 60°C for prepolymerization. Control the polymerization reaction time, when the pre-polymerization conversion rate is 22.5%, mix the partially pre-polymerized styrene thick emulsion and butyl acrylate thick emulsion according to the volume ratio of 4/1, and add macromolecules with a total monomer volume of 3.6% The monomer polyethylene glycol diacrylate is mixed evenly and placed in a water bath at 40° C. to continue the reaction for 28 hours, so that the conversion rate of the monomer can reach more than 96%. After the reaction, a powdery polymer product was obtained.

Example 2

On the basis of Example 1, the concentration of the sodium lauryl sulfate aqueous solution was changed to 5.0 g/100 ml H ₂ O. After mixing the styrene concentrated emulsion with a prepolymerization conversion rate of 22.5% and the butyl acrylate concentrated emulsion according to the volume ratio of 1/1, add macromonomer polyethylene glycol diacrylate with a total monomer volume of 4.5%, After mixing evenly, put it into a water bath at 60° C. to continue the reaction for 20 hours, so that the monomer conversion rate reaches 96%. After the reaction, a powdery polymer product was obtained.

Example 3

On the basis of Example 1, the prepolymerization temperature was changed to 50°C. After mixing the styrene concentrated emulsion with a prepolymerization conversion rate of 15% and the butyl acrylate concentrated emulsion according to the volume ratio of 1/1, add macromonomer polyethylene glycol diacrylate with a total monomer volume of 6.75%, After mixing evenly, put it into a water bath at 60° C. to continue the reaction for 20 hours, so that the conversion rate of the monomer can reach more than 96%. After the reaction, a powdery polymer product was obtained.

Example 4

On the basis of Example 1, the concentration of the sodium lauryl sulfate aqueous solution was changed to 1.0 g/100 ml of water, and the dosage was 5 ml. The volume fraction of the prepared thick emulsion was 75%. After mixing the styrene thick emulsion with a prepolymerization conversion rate of 10.0% and the butyl methacrylate thick emulsion according to the volume ratio of 1/1, add macromonomer polyethylene glycol diacrylic acid with a total monomer volume of 6.75% Esters, after mixing evenly, put them into a water bath at 40°C to continue the reaction for 28 hours, so that the conversion rate of the monomers can reach more than 96%. After the reaction, a powdery polymer product was obtained.

Example 5

On the basis of Example 1, using sodium dodecylsulfonate as an emulsifier and dibenzoyl peroxide as an initiator, the amount of sodium dodecylsulfonate aqueous solution was adjusted to 2ml. The volume fraction of the prepared thick emulsion is 88.2%. After mixing the styrene thick emulsion with a prepolymerization conversion rate of 10.0% and the butyl methacrylate thick emulsion according to the volume ratio of 1/4, add macromonomer polyethylene glycol diacrylic acid with a total monomer volume of 6.75% After mixing the esters evenly, put them into a water bath at 80° C. to continue the reaction for 14 hours, so that the conversion rate of the monomers can reach more than 96%. After the reaction, a powdery polymer product was obtained.

Claims (6)

1. a polystyrene/polyacrylic ester adopts concentrated emulsion polymeric method from the preparation method of increase-volume high polymer alloy, comprises the pre-polymerization of polystyrene and acrylic ester monomer concentrated emulsion and adds the polymerization of macromonomer; Concrete steps are as follows:

A: the preparation volume fraction is polystyrene and the acrylic ester monomer concentrated emulsion of 75-89%, carries out pre-polymerization respectively under 40-60 ℃, and extremely monomeric transformation efficiency is 10-25%;

B: polystyrene and acrylic ester monomer concentrated emulsion after the pre-polymerization that steps A is obtained mix with the volume ratio of 1/4-4/1, add macromonomer and initiator, macromolecular add-on is the 3.6-6.75% of monomer cumulative volume, the initiator add-on is 0.5% of a monomer total mass, under 40-80 ℃, carry out polyreaction, reach 96% when above to monomeric total conversion rate, finish reaction, the collection product;

Said macromonomer is that two ends have polymerizable double bond, middle segment is the oligopolymer of hydrophilic radical among the above-mentioned steps B, and initiator is azo class or organic peroxy class initiator.

2. according to the preparation method of claim 1, it is characterized in that: preparation polystyrene and the used tensio-active agent of acrylic ester monomer concentrated emulsion are anion surfactant in the steps A, and consumption is 1.0-8.0g/100ml H ₂O, the volume fraction of prepared monomer concentrated emulsion is 79%.

3. according to the preparation method of claim 1, it is characterized in that: it is 1/1 that polystyrene among the step B after the pre-polymerization and acrylic ester monomer concentrated emulsion carry out the blended volume ratio.

4. according to the preparation method of claim 1, it is characterized in that: macromolecular add-on is 6.75% of a monomer cumulative volume.

5. according to the preparation method of claim 1, it is characterized in that: styrenic monomers is meant vinylbenzene or has C on phenyl ring ₁To C ₁₅The substituent styrene derivatives of aliphatics; The monomeric molecular formula of acrylic ester is CH ₂C (R ₁) COOR ₂, R wherein ₁=H, CH ₃R ₂=C ₁-C ₂₀Alkyl; Used macromole is a polyethyleneglycol diacrylate among the step B; Initiator is Diisopropyl azodicarboxylate or dibenzoyl peroxide.

6. according to the preparation method of claim 1 or 2, it is characterized in that: used tensio-active agent is sodium lauryl sulphate or sodium laurylsulfonate.

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