接枝SAN分子量对ABS树脂性能和形态结构的影响

采用种子乳液聚合法在聚丁二烯乳胶粒上接枝共聚苯乙烯和丙烯腈、通过改变共聚单体中叔十二烷基硫醇（TDDM）的用量，合成了一系列PB-g-SAN共聚物，将这些共聚物与SAN树脂熔融共混制得了ABS树脂，研究了单体中TDDM含量对SAN在PB上的接枝率、SAN的分子量及ABS树脂的性能和形态结构的影响，结果发现，SAN在PB上的接枝率及其分子量随TDDM含量的增加而下降，在单体中无TDDM时，PB-g-SAN共聚物的增韧效果变差导致了ABS村脂的冲击强度较低，引入TDDM后明显地改善了ABS树脂的冲击韧性和加工性能。形态结构研究结果表明，单体中TDDM的含量显著地影响着PB橡胶粒子的内部结构，随着TDDM含量的增加，橡胶粒子中SAN包容结构的尺寸增大。

The Effect of the Molecular Weight of SAN Copolymer Grafted onto PB Rubber Particles on Morphology and Property of ABS Resins

A series of PB g SAN copolymers were synthesized by grafting copolymering styrene and acrylonitrile monomer onto polybutadiene(PB) latex rubber particles with different contents of tert dodecyl mercaptan(TDDM) in the comonomer using the seeded emulsion polymerization technique. By blending these copolymers with SAN resins, ABS resins were prepared. The influence of TDDM content on the grafting degree and the molecular weight of SAN copolymer, the morphology and properties of ABS resins were then investigated. It is found that the grafting degree and the molecular weight of the SAN copolymer decreased with increasing TDDM content in the comonomer. When there is no TDDM in the comonomer, a decrease of toughening effict of PB g SAN copolymer results in a decrease of the impact strength of the ABS resin. The impact toughness and processing properties of the ABS resin is improved after introducing TDDM into the comonomer. The morphological results show that TDDM significantly affects the internal structure of the PB rubber particles. The size of the SAN subinclusions dispersed in the PB rubber particles increases with increasing TDDM content in the comonomer.