核壳结构微纳橡胶粒子的可控合成及对PPO/PS共混体系的增韧

Controllable Synthesis of Sub-Micrometer Core-Shell Structural Rubber Particles and its Toughening Modification for PPO/PS blends

采用乳液聚合方法在粒径为100 nm的聚丁二烯(PB)胶乳上接枝聚合苯乙烯(St),合成了核壳比为70/30(PB/PS)的PB-g-PS接枝共聚物,将其与聚苯醚(PPO)、聚苯乙烯(PS)树脂熔融共混,制备出一系列橡胶含量、基体组成不同的PPO/PS/PB-g-PS共混物,并考察了共混物的相容性、力学性能及形态结构。结果发现:PPO与PS为完全相容体系,且PB-g-PS在PPO/PS基体中的均匀分散程度随体系中PPO引入量的增大而明显改善,共混物的冲击强度及屈服强度也随之逐渐增大,进而促使共混物发生脆-韧转变所需的橡胶含量逐渐降低;随着共混体系中橡胶含量的增加,共混物的冲击强度逐渐提高,而屈服强度却逐渐降低,共混物的韧性断裂特征越发显著。

Sub-micrometer PB-g-PS graft copolymer was synthesized with emulsion polymerization by grafting styrene(St)onto polybutadiene(PB)latex particles(100 nm),a fixed ratio of St to PB(70:30)was added into the reaction system.Then,the core-shell rubber particles were blended with polyphenylene oxide(PPO)and polystyrene(PS),a series of PPO/PS/PB-g-PS blends with the different matrix composition and rubber content were obtained,and the compatibility,mechanical properties,morphology structure of the blends were studied.The results showed that PPO and PS were miscible in all ranges of compositions.With the increase of PPO content in the matrix,the dispersion of PB-g-PS graft copolymers in PPO/PS matrix was dramatically improved,the impact strength and yield strength obvious increased,while the brittle-ductile transition of the blends shifts to low rubber content.The increase of the rubber content in the blends results in a continuous increase of the impact strength and an obvious decrease of the yield strength,and the characteristics of ductile fracture became increasingly obvious.