N-phenylmaleimide (PMI) was introduced into the copolymers as a heat-resistant component, which could significantly improve the thermal resistance of the copolymers. It was initially copolymerized with Man and St, then dehydrated with anhydride on the main chain of the polymer to form a phenylimide structure. Binary copolymers such as PMI and ST and PMI/St/P were synthesized. MMA, PMI / St / AN and other terpolymer, Japan Mitsubishi Liyang Corporation has synthesized ABS (butadiene - styrene - acrylonitrile) heat resistant modifier SAM - 2, and is in the market promotion. Zhao Xingang and Yu Zhenhuan of the Research Institute of Jilin Petrochemical Company have synthesized the corresponding heat-resistant modifiers by two methods. By improving the compatibility of matrix resin and grafted layer resin, a heat-resistant ABS resin with good comprehensive properties has been prepared.

N-phenylmaleimide was dissolved in styrene and acrylonitrile to form a solution with styrene, acrylonitrile and N-phenylmaleimide as copolymer monomers. Sodium dodecyl sulfonate as emulsifier and CHP-iron redox system as initiator were used to synthesize heat-resistant modifier at 70 C. The molecule was optimized in the process of formulation design. The emulsion polymerization products with similar molecular weight of polymer obtained by solution polymerization were synthesized.

Butadiene latex was coagulated and then swelled in styrene, N-phenylmaleimide was dissolved in styrene and acrylonitrile to form a solution. Finally, toluene was used as solvent to polymerize for 6 hours, then cooled, the polymer solution was dissolved in trichloromethane, precipitated with methanol, filtered and repeated in methanol. Pure polymer, butadiene-styrene-acrylonitrile-N-phenylmaleimide copolymer, was obtained by filtration and drying after washing. The final yield was 97%.

The self-made heat-resistant modifier and SAM-2 of Mitsubishi Liyang Corporation were used as heat-resistant modifier, PW-151 powder produced by synthetic resin factory was used as impact modifier, and the resin based on SAN-T was extruded and pelleted in a twin-screw extruder at 210 C. Finally, two kinds of samples were obtained by injection molding at 230 C.

Through the analysis and test of the heat-resistant ABS copolymer samples synthesized by the above different methods, the results show that PMI is a kind of heat-resistant modification component in Colleges and universities, with each addition of one part of the material, the Vicat softening point can be increased by 23 C; the impact strength of ABS will be affected by the introduction of PMI in varying degrees; the grafting rate will be increased and the modification will be carried out. Good chemical composition of grafting layer resin and matrix resin can effectively improve the impact strength of materials; solution polymerization can effectively improve the grafting rate, ensure that the chemical composition of grafting layer resin and matrix resin is similar, and produce heat-resistant ABS resin with excellent comprehensive properties.