Maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere as well as preparation method and application thereof
阅读说明：本技术 马来酸酐/醋酸乙烯酯/苯乙烯/α-甲基苯乙烯共聚物微球及其制备方法与应用 (Maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere as well as preparation method and application thereof ) 是由 张洁 刘振杰 宋文波 邵清 于 2019-10-25 设计创作，主要内容包括：本发明涉及高分子聚合领域,公开一种马来酸酐/醋酸乙烯酯/苯乙烯/α-甲基苯乙烯共聚物微球,所述共聚物微球中的共聚物包含式(1)所示的结构单元、式(2)所示的结构单元、式(3)所示的结构单元和式(4)所示的结构单元；基于共聚物各结构单元的总摩尔量,所述式(1)所示结构单元的摩尔含量为47-50％,式(2)所述结构单元的摩尔含量为10-15％,式(3)结构单元的摩尔含量为10-15％；式(4)所述结构单元的摩尔含量为18-32％。所述共聚物微球粒径均匀,且颗粒表面洁净,制备工艺简单,够作为耐热改性剂用于聚合物,特别是聚丙烯,以改善聚合物的耐热性能。(The invention relates to the field of high molecular polymerization, and discloses maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres, wherein a copolymer in the copolymer microspheres comprises a structural unit shown in a formula (1), a structural unit shown in a formula (2), a structural unit shown in a formula (3) and a structural unit shown in a formula (4); the molar content of the structural unit shown in the formula (1) is 47-50%, the molar content of the structural unit shown in the formula (2) is 10-15%, and the molar content of the structural unit shown in the formula (3) is 10-15% based on the total molar amount of all the structural units of the copolymer; the molar content of the structural unit in the formula (4) is 18-32%. The copolymer microsphere has uniform particle size, clean particle surface and simple preparation process, and can be used as a heat-resistant modifier for polymers, particularly polypropylene, so as to improve the heat resistance of the polymers.)
1. A maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere, wherein a copolymer in the copolymer microsphere comprises a structural unit represented by formula (1), a structural unit represented by formula (2), a structural unit represented by formula (3) and a structural unit represented by formula (4);
the molar content of the structural unit shown in the formula (1) is 47-50%, the molar content of the structural unit shown in the formula (2) is 10-15%, and the molar content of the structural unit shown in the formula (3) is 10-15% based on the total molar amount of all the structural units of the copolymer; the molar content of the structural unit in the formula (4) is 18-32%.
2. The copolymer microspheres of claim 1, wherein the molar content of the structural unit represented by formula (1) is 48 to 50%, the molar content of the structural unit represented by formula (2) is 10 to 15%, and the molar content of the structural unit represented by formula (3) is 10 to 15%; the molar content of the structural unit in the formula (4) is 18-30%.
3. The copolymer microsphere according to claim 1 or 2, wherein the average particle size of the copolymer microsphere is 400-1500nm, preferably 600-1500 nm.
4. A method for preparing maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres, the method comprising the steps of:
(1) dissolving a polymerization monomer and an initiator in an organic solvent in an inert atmosphere to form a homogeneous solution;
(2) after the homogeneous solution is subjected to polymerization reaction to obtain copolymer emulsion suspension, performing centrifugal separation to obtain the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres;
wherein the polymerization monomer is a comonomer I, a comonomer II, a comonomer III and a comonomer IV;
the comonomers I to IV respectively have structures shown in formulas (5) to (8)
5. The production method according to claim 4, wherein the mass concentration of the polymerized monomer is 5 to 25 wt%, preferably 10 to 20 wt%, based on the total weight of the homogeneous solution;
preferably, the comonomer I is used in an amount of 40 to 50 wt%, the comonomer II is used in an amount of 5 to 15 wt%, the comonomer III is used in an amount of 7 to 14 wt%, and the comonomer IV is used in an amount of 25 to 41 wt%, based on the total weight of the polymerized monomers;
more preferably, the comonomer I is used in an amount of 41 to 47 wt%, the comonomer II is used in an amount of 7 to 10 wt%, the comonomer III is used in an amount of 9 to 13 wt%, and the comonomer IV is used in an amount of 29 to 41 wt%, based on the total weight of the polymerized monomers.
6. The production method according to claim 4 or 5, wherein the initiator is an organic peroxide and/or an azo compound;
preferably, the organic peroxide is selected from at least one of dibenzoyl peroxide, dicumyl peroxide, ditert-butyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate;
preferably, the azo compound is selected from azobisisobutyronitrile and/or azobisisoheptonitrile;
preferably, the mass concentration of the initiator is from 0.2 to 3.8 wt.%, preferably from 0.5 to 3.5 wt.%, more preferably from 1 to 3 wt.%, based on the total weight of the homogeneous solution.
7. The production method according to any one of claims 4 to 6, wherein the organic solvent is an organic acid alkyl ester;
preferably, the organic acid alkyl ester has the general formula R1COOR2Wherein R is1Selected from H, C1-4At least one of alkyl, phenyl and benzyl of (A), R2Is C1-10Alkyl groups of (a);
more preferably, R1Is C1-4Alkyl and/or phenyl of R2Is C1-7Alkyl groups of (a);
more preferably, the organic solvent is selected from at least one of ethyl formate, propyl formate, isobutyl formate, pentyl formate, ethyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isoamyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isoamyl butyrate, ethyl isovalerate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, and ethyl phenylacetate.
8. The production method according to any one of claims 4 to 7, wherein the conditions of the polymerization reaction include: the polymerization temperature is 66-86 ℃, preferably 68-85 ℃; the polymerization time is 4 to 20 hours, preferably 4 to 8 hours.
9. Maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres prepared by the preparation method of any one of claims 4-8, wherein the average particle size of the copolymer microspheres is 400-1500nm, preferably 600-1500 nm.
10. Use of maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres according to any one of claims 1-3 and 9 as a heat resistance modifier in a polymer, preferably said polymer is polypropylene.
Technical Field
The invention relates to the field of high polymer polymerization, in particular to maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres and a preparation method and application thereof.
Background
The maleic anhydride-containing copolymers are mostly prepared by solution or conventional precipitation polymerization. Shenrong et al "Styrene-maleic anhydride copolymerization in different solvents" in the text, a polymer of maleic anhydride and styrene was prepared by reacting maleic anhydride and styrene in ethyl acetate and N, N-dimethylformamide, after completion of the reaction, by using ethanol as a precipitant (proceedings of Wuhan university of engineering, 2019,41 (1): 65-68).
In "Synthesis of styrene-maleic anhydride alternating copolymer with Low relative molecular weight" in Liuting nations et al, styrene-maleic anhydride copolymer was synthesized in toluene by precipitation polymerization.
Synthesis and characterization of styrene-maleic anhydride random copolymer in Green solvent by Gekko Swinhonis et al (plastics science 2019,47(2):24-28) styrene-maleic anhydride random copolymer was prepared by solution polymerization using dimethyl carbonate as a Green solvent.
Multipolymers of maleic anhydride have many uses. In the study of 'alpha-methylstyrene/styrene/maleic anhydride terpolymer functional polypropylene and compatibilized polypropylene/nylon 6 blending system' (journal of high molecular science, 2011, 2: 180-type 185), the Liangshujun and the like synthesize the terpolymer of maleic anhydride, styrene and alpha-methylstyrene by taking butanone as a solvent, and the terpolymer has an in-situ compatibilization effect on the polypropylene/nylon 6 blending system, so that the particle size of the dispersed phase nylon 6 is obviously reduced.
In the prior art, the copolymer containing maleic anhydride is not mentioned as a heat-resistant modifier to be added to a polymer system such as polyolefin.
Disclosure of Invention
The invention aims to improve the heat-resistant temperature of a polymer, and provides maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres and a preparation method and application thereof. The copolymer microsphere has uniform particle size, clean particle surface and simple preparation process, and can be used as a heat-resistant modifier for polymers, particularly for remarkably improving the heat resistance of polypropylene.
In order to achieve the above object, a first aspect of the present invention provides maleic anhydride/vinyl acetate/styrene/α -methylstyrene copolymer microspheres, wherein a copolymer in the copolymer microspheres comprises a structural unit represented by formula (1), a structural unit represented by formula (2), a structural unit represented by formula (3), and a structural unit represented by formula (4);
the molar content of the structural unit shown in the formula (1) is 47-50%, the molar content of the structural unit shown in the formula (2) is 10-15%, and the molar content of the structural unit shown in the formula (3) is 10-15% based on the total molar amount of all the structural units of the copolymer; the molar content of the structural unit in the formula (4) is 18-32%.
In a second aspect, the present invention provides a method for preparing maleic anhydride/vinyl acetate/styrene/α -methylstyrene copolymer microspheres, comprising the steps of:
(1) dissolving a polymerization monomer and an initiator in an organic solvent in an inert atmosphere to form a homogeneous solution;
(2) after the homogeneous solution is subjected to polymerization reaction to obtain copolymer emulsion suspension, performing centrifugal separation to obtain the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres;
wherein the polymerization monomer is a comonomer I, a comonomer II, a comonomer III and a comonomer IV;
the comonomers I to IV respectively have structures shown in formulas (5) to (8)
In a third aspect, the invention provides maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres prepared by the preparation method of the invention.
In a fourth aspect, the invention provides an application of the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere.
Through the technical scheme, the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere provided by the invention and the preparation method and application thereof have the following beneficial effects:
the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres provided by the invention realize self-stabilization precipitation polymerization reaction of the comonomer I, the comonomer II, the comonomer III and the comonomer IV by selecting a specific organic solvent and matching the organic solvent with a specific amount of monomers, and the polymer microspheres can realize excellent dispersibility in the organic solvent without adding any stabilizers, co-stabilizers and other auxiliaries in a polymerization reaction system, and the microspheres are not coagulated, so that the surfaces of the obtained polymer microspheres are clean and pollution-free, the particle size of the microspheres can be controlled, and the polymer microspheres with the particle size range of 400-1500nm can be obtained.
Furthermore, the composite microsphere provided by the invention can be used as a heat-resistant modifier in polymers, particularly polypropylene, and can significantly improve the heat resistance of the polymers.
Drawings
FIG. 1 is an infrared spectrum of the copolymer of example 1;
FIG. 2 is a scanning electron micrograph of the copolymer of example 1.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres, wherein a copolymer in the copolymer microspheres comprises a structural unit shown in a formula (1), a structural unit shown in a formula (2), a structural unit shown in a formula (3) and a structural unit shown in a formula (4);
the molar content of the structural unit shown in the formula (1) is 47-50%, the molar content of the structural unit shown in the formula (2) is 10-15%, and the molar content of the structural unit shown in the formula (3) is 10-15% based on the total molar amount of all the structural units of the copolymer; the molar content of the structural unit in the formula (4) is 18-32%.
In the invention, the specific comonomer is copolymerized according to the dosage ratio limited by the invention, so that the obtained maleic anhydride/vinyl acetate/styrene/alpha-methyl styrene copolymer has microspheres with good uniformity.
Furthermore, in order to obtain copolymerized microspheres with more excellent performance and more uniform microsphere morphology, the molar content of the structural unit shown in the formula (1) is 48-50%, the molar content of the structural unit shown in the formula (2) is 10-15%, and the molar content of the structural unit shown in the formula (3) is 10-15%, based on the total molar amount of the structural units of the polymers; the molar content of the structural unit in the formula (4) is 18-30%.
In the present invention, the total of the molar contents of the structural unit represented by the formula (1), the structural unit represented by the formula (2), and the structural unit (3) is 100%.
In the present invention, the content of each structural unit in the copolymer is used1H NMR is used for testing, and the testing method is to pass1And calculating the ratio of the peak area corresponding to the characteristic hydrogen in the corresponding structural unit in H NMR.
According to the invention, the average particle size of the copolymer microspheres is 400-1500nm, preferably 600-1500 nm.
In a second aspect, the present invention provides a method for preparing maleic anhydride/vinyl acetate/styrene/α -methylstyrene copolymer microspheres, comprising the steps of:
(1) dissolving a polymerization monomer and an initiator in an organic solvent in an inert atmosphere to form a homogeneous solution;
(2) after the homogeneous solution is subjected to polymerization reaction to obtain copolymer emulsion suspension, performing centrifugal separation to obtain the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres;
wherein the polymerization monomer is a comonomer I, a comonomer II, a comonomer III and a comonomer IV;
the comonomers I to IV respectively have structures shown in formulas (5) to (8)
In the invention, a copolymerization mode is adopted, a specific comonomer is copolymerized according to the method provided by the invention to obtain the copolymer microsphere, and the prepared maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere has good uniformity.
In the invention, the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microsphere is obtained by copolymerizing a comonomer I, a comonomer II, a comonomer III and a comonomer IV. Specifically, the introduction of the comonomer I, the comonomer II and the comonomer IV enables a self-stabilizing system to be formed in a polymerization process, so that the polymer microspheres are uniformly dispersed in an organic solvent, and agglomeration does not occur among the microspheres.
According to the invention, the concentration by mass of the polymerized monomers is from 4 to 22% by weight, preferably from 10 to 20% by weight, based on the total weight of the homogeneous solution.
According to the invention, the comonomer I is used in an amount of 40 to 50 wt%, the comonomer II is used in an amount of 5 to 15 wt%, the comonomer III is used in an amount of 7 to 14 wt%, and the comonomer IV is used in an amount of 25 to 41 wt%, based on the total weight of the polymerized monomers.
In the invention, in order to obtain maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres with uniform particles and excellent morphology, the inventor researches the respective use amounts of the comonomer I, the comonomer II, the comonomer III and the comonomer IV in the polymerization process, and the research shows that when each of the comonomers meets the range, the prepared quadripolymer microspheres have uniform particles, excellent particle morphology and clean particle surfaces.
Still further, the comonomer I is used in an amount of 41 to 47 wt%, the comonomer II is used in an amount of 7 to 10 wt%, the comonomer III is used in an amount of 9 to 13 wt%, and the comonomer IV is used in an amount of 29 to 41 wt%, based on the total weight of the polymerized monomers.
According to the invention, the initiator is an organic peroxide and/or an azo compound.
According to the present invention, the organic peroxide is at least one selected from the group consisting of dibenzoyl peroxide, dicumyl peroxide, ditert-butyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate.
According to the invention, the azo compound is selected from azobisisobutyronitrile and/or azobisisoheptonitrile.
According to the invention, the mass concentration of the initiator is between 0.2% and 3.8% by weight, preferably between 0.5 and 3.5% by weight, more preferably between 1 and 3% by weight, based on the total weight of the homogeneous solution.
According to the invention, the organic solvent is an organic acid alkyl ester.
In the invention, organic acid alkyl ester is selected as an organic solvent, and can be matched with the comonomer I, the comonomer II, the comonomer III and the comonomer IV with specific dosage, so that the self-stabilization precipitation polymerization reaction of the comonomer I, the comonomer II, the comonomer III and the comonomer IV can be realized, no stabilizer or co-stabilizer is required to be added in a polymerization reaction system, the self-stabilization dispersion effect is realized, and the surface of the obtained polymer microsphere is clean and pollution-free.
According to the invention, the organic acid alkyl ester has the general formula R1COOR2Wherein R is1Selected from H, C1-4At least one of alkyl, phenyl and benzyl of (A), R2Is C1-10Alkyl group of (1).
Preferably, R1Is C1-4Alkyl and/or phenyl of R2Is C1-7Alkyl group of (1).
Still further, the organic solvent is at least one selected from the group consisting of ethyl formate, propyl formate, isobutyl formate, pentyl formate, ethyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isoamyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isoamyl butyrate, ethyl isovalerate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate, and ethyl phenylacetate.
In the present invention, the total amount of the comonomer I, the comonomer II, the comonomer III, the comonomer IV, the initiator and the organic solvent is 100 wt%.
According to the invention, the polymerization conditions comprise: the polymerization temperature is 66-86 ℃, preferably 68-85 ℃; the polymerization time is 4 to 20 hours, preferably 4 to 8 hours.
In the present invention, a water bath and/or an oil bath is used to provide the heat required for the polymerization of the present invention.
In the present invention, the polymerization reaction is carried out in an inert atmosphere, preferably a nitrogen atmosphere.
In the invention, the copolymer emulsion suspension obtained by the polymerization reaction is separated by adopting a solid-liquid separation mode to obtain the maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres.
In the present invention, a solid-liquid separation method, preferably, a centrifugal separation method, which is conventional in the prior art, may be employed.
In the invention, when centrifugal separation is adopted, the centrifugal rotating speed is 1000-3000rad/min, and the centrifugal time is 10-30 min.
The third aspect of the present invention provides maleic anhydride/vinyl acetate/styrene/alpha-methylstyrene copolymer microspheres prepared by the preparation method of the present invention, wherein the average particle size of the copolymer microspheres is 400-1500nm, preferably 600-1500 nm.
In a fourth aspect, the present invention provides the use of the maleic anhydride/vinyl acetate/styrene/α -methylstyrene copolymer microspheres of the present invention as a heat-resistant modifier in a polymer, preferably, the polymer is polypropylene.
In the present invention, the maleic anhydride/vinyl acetate/styrene/α -methylstyrene copolymer microspheres are used in an amount of 0.2 to 2 wt%, preferably 0.4 to 1.2 wt%, relative to the total weight of the polymer.
The present invention will be described in detail below by way of examples. In the following examples of the present invention,
the polymerization yield (C) was determined by the following formulap) Perform calculation
Cp＝Mp×100％/Mm
Wherein Mp is the mass of the resulting polymer; mm is the total mass of monomers added.
Observing and measuring the shape and the size of the copolymer microsphere by adopting a Scanning Electron Microscope (SEM);
the infrared spectrogram of the copolymer is tested by FI-IR;
the content of each structural unit in the copolymer is adopted1H NMR is used for testing, and the testing method is to pass1Measuring the content of each structural unit according to the ratio of the peak areas corresponding to the characteristic hydrogen in the corresponding structural unit in H NMR;
the heat resistance of the polypropylene is measured by a GB/T1634.2-2004 method;
comonomer I, having the structure of formula (5), was purchased from carbofuran technologies, Inc.;
comonomer II, having the structure shown in formula (6), was purchased from carbofuran technologies, Inc.;
comonomer III, having the structure shown in formula (7), was purchased from carbofuran technologies, Inc.;
comonomer IV, having the structure shown in formula (8), was purchased from carbofuran technologies, Inc.
Polypropylene K8009, available from china and korea petrochemical company.
Examples and comparative examples all other materials were commercially available.
Example 1
10g of comonomer I, 1g of azobisisobutyronitrile, 5.9g of comonomer IV, 2.15g of comonomer II, 2.6g of comonomer III and 87.8g of isoamyl acetate are added into a 500mL three-neck flask, after the materials are uniformly mixed, nitrogen is introduced for 20 minutes, the three-neck flask is moved into a 70 ℃ water bath for reaction for 5 hours, after the reaction is finished, the obtained polymer emulsion suspension is centrifugally separated for 20 minutes by a centrifuge at the rotating speed of 2000rad/min to obtain polymer microspheres A114.57g, and the corresponding polymer yield is 71.2%. The particle size of the polymer microspheres is 1200 nm.
Subjecting the polymer microsphere A1 to1H NMR measurement of the total molar amount of the structural units in the polymerThe molar content of the structural unit shown in the formula (1) is 48 percent, the molar content of the structural unit shown in the formula (2) is 15 percent, and the molar content of the structural unit shown in the formula (3) is 15 percent; the molar content of the structural unit represented by the formula (4) is 32%.
As can be seen from FIG. 1, 1786cm-1、1890cm-1Characteristic absorption peak of anhydride group, 1250cm-1Is an absorption peak of a C-O bond and is 709cm-1Is the absorption peak of the phenyl function of C-O, on the basis of which the polymer can be identified as a copolymer of maleic anhydride-vinyl acetate-alpha-methylstyrene-styrene.
FIG. 2 is an SEM image of copolymer microspheres, from which it can be seen that the particles of the copolymer microspheres are uniform and the surfaces of the particles are clean and uncontaminated.
Example 2
9.6g of comonomer I, 0.8g of azobisisobutyronitrile, 7.08g of comonomer IV, 1.72g of comonomer II, 2.08g of comonomer III and 88g of butyl butyrate are added into a 500mL three-neck flask, after the materials are uniformly mixed, nitrogen is introduced for 20 minutes, the three-neck flask is moved into a water bath at 60 ℃ for reaction for 24 hours, after the reaction is finished, the obtained polymer emulsion suspension is centrifugally separated for 20 minutes by a centrifuge at the rotating speed of 2000rad/min to obtain polymer microspheres A214.63g, and the corresponding polymer yield is 70.7%. The particle size of the polymer microsphere is 1500 nanometers. The obtained polymer is a quadripolymer of maleic anhydride, styrene, alpha-methyl styrene and vinyl acetate, and the molar content of the maleic anhydride in the copolymer is 50%.
Subjecting the polymer microsphere A2 to1H NMR measurement shows that the molar content of the structural unit shown in the formula (1) is 50%, the molar content of the structural unit shown in the formula (2) is 15% and the molar content of the structural unit shown in the formula (3) is 15% based on the total molar amount of the structural units in the polymer; the molar content of the structural unit in the formula (4) is 20%
Example 3
10.2g of comonomer I, 0.2g of azobisisobutyronitrile, 8.26g of comonomer IV, 2.58g of comonomer II, 3.12g of comonomer III and 87.8g of butyl benzoate are added into a 500mL three-neck flask, after the materials are uniformly mixed, nitrogen is introduced for 20 minutes, the three-neck flask is moved into a water bath at 90 ℃ for reaction for 3 hours, after the reaction is finished, the obtained polymer emulsion suspension is centrifugally separated for 20 minutes by a centrifuge at the rotating speed of 2000rad/min to obtain 316.36g of polymer microspheres, and the corresponding polymer yield is 68.9%. The particle size of the polymer microsphere is 1500 nanometers.
Subjecting the polymer microsphere A3 to1H NMR measurement shows that the molar content of the structural unit shown in the formula (1) is 47 percent, the molar content of the structural unit shown in the formula (2) is 10 percent and the molar content of the structural unit shown in the formula (3) is 15 percent based on the total molar amount of all the structural units in the polymer; the molar content of the structural unit of the formula (4) is 28%.
Example 4
9.8g of comonomer I, 0.89g of azobisisobutyronitrile, 9.44g of comonomer IV, 1.72g of comonomer II, 2.08g of comonomer III and 87.8g of isoamyl isovalerate are added into a 500mL three-neck flask, nitrogen is introduced for 20 minutes after the materials are uniformly mixed, the three-neck flask is moved into a 70 ℃ water bath for reaction for 5 hours, and after the reaction is finished, the obtained polymer emulsion suspension is centrifugally separated for 20 minutes by a centrifuge at the rotating speed of 2000rad/min to obtain 412.66g of polymer microspheres, wherein the corresponding polymer yield is 54.9%. The polymeric microspheres were 1300 nm in size.
Subjecting the polymer microsphere A4 to1H NMR measurement shows that the molar content of the structural unit shown in the formula (1) is 48%, the molar content of the structural unit shown in the formula (2) is 10% and the molar content of the structural unit shown in the formula (3) is 10% based on the total molar amount of the structural units in the polymer; the molar content of the structural unit represented by the formula (4) is 32%.
Example 5
Adding 2.45g of comonomer I, 0.2g of azobisisobutyronitrile, 1.48g of comonomer IV, 0.53g of comonomer II, 0.65g of comonomer III and 87.8g of isoamyl acetate into a 500mL three-neck flask, uniformly mixing the materials, introducing nitrogen for 20 minutes, moving the three-neck flask into a 70 ℃ water bath, reacting for 5 hours, and after the reaction is finished, centrifuging and separating the obtained polymer emulsion suspension by a centrifuge at the rotating speed of 2000rad/min for 20 minutes to obtain polymer microspheres A53 g, wherein the corresponding polymer yield is 50%. The particle size of the polymer microsphere is 400 nm.
Subjecting the polymer microsphere A5 to1H NMR measurement shows that the molar content of the structural unit shown in the formula (1) is 48%, the molar content of the structural unit shown in the formula (2) is 15% and the molar content of the structural unit shown in the formula (3) is 15% based on the total molar amount of the structural units in the polymer; the molar content of the structural unit represented by the formula (4) is 32%.
Comparative example 1
Copolymer microspheres were prepared according to the method of example 1, except that: butanone is used to replace isoamyl acetate. A solution of the polymer is obtained without obtaining a dispersion of polymeric microspheres.
Comparative example 2
Copolymer microspheres were prepared according to the method of example 1, except that: the amount of comonomer I was 20g, the amount of comonomer II was 17g, the amount of comonomer III was 10g and the amount of comonomer IV was 12 g. After the polymerization is completed, the polymer system is a coagulated solid, and a dispersion system of the polymer microspheres is not obtained.
Test example
The polymer microspheres prepared in the examples and comparative examples were mixed with polypropylene in the amounts shown in table 1, and then subjected to extrusion granulation to obtain polypropylene particles. The screw rotating speed of the extruder is 110r/min, the barrel temperature of the extruder is set to be 175-.
The polypropylene and the polypropylene pellets were subjected to a heat resistance test in accordance with GB/T1634.2-2004, and the results are shown in Table 1.
TABLE 1
Test example
Polymeric microspheres in an amount
Heat distortion temperature DEG C
Flexural modulus GPa
1
A1，0.4wt％
82.6
1.24
2
A1，0.8wt％
83,3
1.23
3
A1，1.2wt％
85.1
1.26
4
A2，1.2wt％
85.3
1.23
5
A3，1.2wt％
85.2
1.25
6
A4，1.2wt％
84.9
1.26
7
A5，1.2wt％
83.8
1.27
9
--
81.2
1.24
As can be seen from Table 1, the composite microspheres of methylstyrene multipolymers provided by the invention are added to polymers as heat-resistant modifiers, so that the heat-resistant performance of the polymers can be improved.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：展色性和阻燃性优异的醋酸乙烯-乙烯共聚乳液