多分散性乙丙嵌段共聚物增韧聚丙烯

首次研究了多分散性乙丙嵌段共聚物(EP)对PP的增韧作用,发现有非常好的增韧效果。添加15%的EP,PP的冲击强度即可达到298J/m。用光学显微镜、SEM、DSC和IR对IPP/PEP共混体系进行了表征和研究,结果发现,由于EP本身特殊的组成及链结构,使其与PP基体具有良好的相容性,分散相在基体中的粒径约为0.2μm～0.4μm之间;同时还发现EP对PP球晶有插入、分割和细化作用。

乙丙嵌段共聚物改性PP/EPR共混物

以乙丙嵌段共聚物(EP)作为增容剂,采用熔融共混的方法制备了聚丙烯(PP)/二元乙丙橡胶(EPR)共混物,通过冲击试验机、电子万能试验机、动态力学分析仪、扫描电子显微镜、偏光显微镜、差示扫描量热仪、平板流变仪、熔体流动速率仪等,研究了EP添加量对PP/EPR共混物力学性能、分散相聚集态结构及加工性能的影响。结果表明,EP对PP/EPR共混物具有良好的增容作用,降低了PP相的熔点和结晶规整性,提高了PP相的结晶温度和结晶度,当EP质量分数为8%时,分散相EPR粒子直径最小、PP和EPR相容性最好,此时共混物的缺口冲击强度和断裂伸长率达到最大值,加工性能最好。

Effect of polyoxypropylene chain length on the critical micelle concentration of propylene oxide-ethylene oxide block copolymers

In this work, the surface activity of block copolymer nonionic surfactants (RPE) has been determined, i.e., critical micelle concentration (CMC), surface excess concentration (Γ), surface area demand per molecule (A), surface tension at CMC (γCMC). A linear decrease of ln[CMC] vs number of oxypropylene units in copolymer molecule was observed. The change in the work of cohesion per oxypropylene group when passing from molecular into micellar state, calculated from the Shinoda equation, was 0.43kT for the studied compounds.