聚丙烯/蒙脱土纳米复合树脂的结构、形态与性能

利用球形纳米蒙脱土(MMT)负载Ziegler-Natta催化剂制备了聚丙烯(PP)/MMT纳米复合树脂。复合树脂中的PP具有与普通PP相仿的等规度和熔点;可通过改变聚合条件调节复合树脂中PP的相对分子质量和MMT含量。采用SEM,WAXRD,POM,DMA,TG等方法研究了复合树脂的形态结构、结晶形态、流变行为、动态力学行为、力学性能、阻隔性能和热稳定性。表征结果显示,复合树脂颗粒呈球形,流动性良好;MMT片层均匀分散于PP基体中,MMT片层与PP基体的相容性较差,在熔融加工过程中会发生部分聚集。当MMT含量约为1.1%(w)时,复合树脂中可形成MMT的逾渗网络。当MMT含量为1.29%(w)时,复合树脂的综合力学性能较好。少量MMT的存在可提高复合树脂的液体阻隔性能和热稳定性。

Structure,Morphology and Properties of Polypropylene/Montmorillonoid Nanocomposite Resins

Polypropylene/montmorillonoid(PP/MMT) nanocomposite resins were prepared by insitu propylene polymerization with a spherical-shaped MMT-supported Ziegler-Natta catalyst.The PP/ MMT resins have similar isotacticity and melting point to those of commercial PP.Both the relative molecular mass of PP and MMT content in the resins are controllable through adjusting polymerization conditions.The performances of the novel resins,including particle morphology,crystal morphology,rheology behavior,dynamic mechanical analysis,mechanical properties,barrier property and thermal stability,were evaluated by SEM,WAXRD,POM,DMA and TG.The results showed that the resins displayed spherical granule morphology and thus was of good fluidity.MMT lamellae were found to be homogeneously dispersed in PP matrix and partially aggregated during the melt resin being processed.The compatibility between MMT lamellae and PP matrix is bad.The MMT lamellae can form percolation network when MMT content is about 1.1%(w).PP/MMT resin with 1.29%(w) MMT content exhibited good comprehensive mechanical properties.Both the liquid barrier properties and thermal stability of the PP/MMT resins could be improved with small MMT content.