抗冲共聚聚丙烯的组成、结构与性能

采用溶剂分级法、黏度法、POM、SEM和DMA等方法对两种抗冲共聚聚丙烯(PPc-A和PPc-B)的分级级分、黏度、晶态结构以及分散相与基体的相容性等进行了研究。分级和黏度分析结果表明,两种共聚聚丙烯中均含乙丙无规共聚物、结晶性乙丙共聚物(BC)和等规聚丙烯(iPP)级分;由于BC在PPc-A中的含量较在PPc-B中高,且PPc-B中橡胶相与基体的黏度差较大,因此虽然两者力学性能接近,但PPc-A的断裂伸长率优于PPc-B。POM,SEM,DMA表征结果显示,PPc-A中的BC可结晶的链段少,晶片尺寸小;PPc-A淬断面中的橡胶相的尺寸较大,橡胶相的均匀程度也高于PPc-B;PPc-A中的橡胶相与iPP基体的相容性好于PPc-B。

Composition,Structure and Properties of Impact Propylene Copolymer

The fraction,viscosity,crystal structure and the compatibility between the disperse phases and the matrixes of two impact propylene copolymers(PPc-A and PPc-B) were studied by means of solvent fractionation,viscosity analysis,POM,SEM and DMA.The results of the fractionation and viscosity analysis indicate that both PPc-A and PPc-B contain fractions of ethylene-propylene random copolymer,crystalline ethylene-propylene copolymer(BC) and isotactic polypropylene(iPP).The elongation at break of PPc-A is much better than that of PPc-B because the higher amount of BC in PPc-A and the larger viscosity difference between the rubber phase and matrix in PPc-B,even though the mechanical properties of PPc-A are similar to those of PPc-B.The characterization results of POM,SEM and DMA show that PPc-A contains fewer and smaller crystallizable segments of BC;the rubber phase in the quenching surface of PPc-A has a bigger size and better uniformity;and the compatibility of the rubber phase and iPP matrix in PPc-A is better.