EPDM-g-MMA对MS树脂的增韧作用

Toughing effect of EPDM-g-MMA on MS resin

用溶液接枝共聚合法合成了三元乙丙橡胶(EPDM)与甲基丙烯酸甲酯(MMA)的接枝共聚物EPDM-g-MMA。红外光谱(FT-IR)分析证实EPDM分子链已接上MMA支链。用EPDM-g-MMA与MMA/苯乙烯(St)共聚物(MS树脂)熔融共混制备耐老化黄变高抗冲塑料(EMS)。研究了EPDM-g-MMA对MS树脂的增韧作用。结果表明:随着EPDM含量的增加,EMS的冲击性能提高,拉伸及弯曲性能下降。在EPDM质量分数为25%时,EMS缺口冲击强度达22.3 kJ/m2,约为MS树脂的15倍。EMS冲击断面形态的扫描电镜(SEM)分析表明,随着EPDM含量增加,其增韧机理由空穴化向轻度剪切屈服转变。

EPDM-g-MMA was synthesized by solution grafting copolymerization of methyl meth- acrylate （MMA） onto ethylene-proplene-diene terpolymer （EPDM）. It was confirmed by FTIR that the branched chain of MMA was grafted on the back-bone of EPDM. The high impact plastics （EMS）, which have excellent resistance to weatherability and yellow discoloration and ageing property, were prepared by blending EPDM-g-MMA with MS resin. The toughing effects of EPDM-g-MMA on MS resin were studied. The results show that the Izod notched impact strength of EMS increased but the tensile strength and the flexural strength decreased with an increase of EPDM content. When the EPDM content was 25%, the notched Izod impact strength of EMS reached 22. 3 kJ/m^2, which is about 15 times of MS resin. SEM micrographs of the fracture surface of EMS show that the toughening mechanism was that the damage mode of cavitation changed into slight shear yielding of matrix with increasing EPDM content.