基体组成及橡胶含量对PPO/PS共混物性能的影响

Influence of Matrix Composition and Rubber Content Modification on Properties of PPO/PS Blends

采用种子乳液聚合法合成了核壳比(PB与PS的质量比)为70/30、粒径为332 nm的PB-g-PS接枝共聚物,然后,将其引入聚苯醚/聚苯乙烯(PPO/PS)共混体系中,研究了基体组成(PPO/PS)及橡胶含量对PPO/PS/PB-g-PS共混物的力学性能、形态结构及断裂机理的影响。研究结果表明,引入PB-g-PS能够显著提高PPO/PS共混物的冲击韧性。随着基体中PPO含量的增加,共混物的冲击强度与屈服强度不断提高,基体发生脆-韧转变所需的橡胶含量逐渐减少,橡胶粒子在基体中的分散状态得到明显改善。随着共混物中橡胶含量的增加,共混物的冲击强度逐渐提高,冲击断面上的韧性断裂特征越发显著,共混物的冲击断裂方式逐渐由脆性断裂转变为韧性断裂。当PPO∶PS=75∶25,且基体中PB的含量为15%时,PPO/PS/PB-g-PS共混物达到了最佳的刚韧平衡,此时,冲击强度增大到610 J/m,而屈服强度仍保持在61 MPa。

PB-g-PS grafting copolymer with core-shell( m( PB)/m( PS)) ratios of 70/30 was synthesized by seed emulsion polymerization with diameter of 332 nm. The core-shell rubber particles were blended with polyphenylene oxide and polystyrene( PPO/PS),and the effects of matrix composition( PPO/PS) and rubber content on the mechanical properties,morphology structure and fracture mechanism of PPO/PS/PB-g-PS blends were studied. The results showed that PB-g-PS copolymer could toughen PPO/PS blends effectively. With the increase of PPO content in the matrix,the impact strength and yield strength increased obviously,the brittle-ductile transition took place of the blends shift to low rubber content and the dispersion of rubber particles in matrix was improved greatly. With the increase of the rubber contents in PPO/PS/PB-g-PS blends,the notched impact strength has been gradually improved, and the characteristics of ductile fracture became increasingly obvious,a transition from brittle fracture to ductile fracture was observed. The stiffness and toughness could be well balanced with the PPO/PS ratio of 75/25,in which the amount of PB was 15%. The impact strength was increased to610 J/m,and the yield strength remained at the level of 61 MPa.