悬浮法EPM—g—SAN的合成与表征

以悬浮法实施二元乙丙橡胶（EPM）与单体苯乙烯（St）和丙烯腈（AN）的接枝共聚反应。合成了EPM—g—SAN，用其与SAN树脂共混制备了高抗冲塑料乙丙橡胶与苯乙烯及丙烯腈的三元共聚物（AES）。研究了AN／St—AN和EPM／St-AN的配料比对接枝反应体系的单体转化率、接枝率和接枝效率及AES缺口冲击强度的影响。用FTIR对EPM—g—SAN所含g—SAN（包括接枝链和非接枝共聚物）的组成进行了定量分析。结果表明，当AN质量分数为35％、EPM质量分数为60％，接枝反应体系的单体转化率、接枝率和接枝效率分别为92％、45％和27．6％。在此条件下合成的EPM—g—SAN对SAN树脂的增韧效率最高，用其制备的AES的悬臂梁缺口冲击强度达到53．2kJ／m^2。FTIR定量分析表明，在EPM—g—SAN的g—SAN中AN单元的平均组成比小于AN单体的配料比，而AN单元在接枝链SAN中的组成比小于在非接枝共聚物SAN中的组成比；当g—SAN所含接枝链的组成与非接枝共聚物的组成相等时，其EPM—g—SAN对SAN树脂有更高的增韧效率。

Suspension grafting copolymerization of EPM-g-SAN and characterization of its product

EPM-g-SAN was synthesized by graft eopolymerization of styrene （St） and acrylonitrile （AN） from ethylene-co-propylene polymer （EPM） with suspension polymerization. The high impact plastics AES were prepared by blending EPM-g-SAN with SAN resin. The effects of the weight frac- tion of monomer AN in the feed comonomer,St-AN （AN/St-AN ratio, wt%） and the weight fraction of EPM in the feed reaction mixture,EPM and St-An -EPM/（EPM＋St-AN）ratio wt%] ,on monomer conversion ratio （CR）, grafting ratio （GR）, grafting efficiency （GE） and the notched Izod impact strength of AES were investigated. FTIR spectroscopy had been applied to quantitative analysis of the composition of copolymer g-SAN contained by EPM-g-SAN. The results showed that when the fraction of monomer AN in the feed St-AN was at 35wt% and the fraction of EPM in the reaction mixture was at 60 wt%,CR,GR and GE were 92%,45% and 27.6% respectively. Under this conditions,the synthesized EPM-g-SAN had a highest toughening effect on SAN resin and the notched Izod impact strength, of AES reached 53. 2 kJ/m^2. The quantitative analysis of FTIR showed that the average weight fraction of AN unit in g-SAN was less than the weight fraction of monomer AN in the feed St- AN,while the weight fraction of AN unit in branched chain SAN was less than that in free copolymer SAN. When the composition of branched chain SAN was the same as that of the free copolymer SAN in g-SAN,the EPM-g-SAN had a highest toughening effect on SAN resin.