聚乙烯-蒙脱土纳米复合材料的结构与性能

利用MgCl2在醇溶剂中可溶解及蒙脱土(MMT)在醇溶剂中发生层间膨胀的特性,制备了负载于MMT层间的MMT-MgCl2-TiCl4催化剂。MgCl2的引入,屏蔽了MMT表面复杂的化学因素对MMT-MgCl2-TiCl4催化剂活性的影响,并起到了高效载体的作用;增大了MMT的层间距,为引入活性中心Ti及活化过程提供了空间,确保MMT-MgCl2-TiCl4催化剂具有很好的活性,同时也为MMT在聚合过程中的层间剥离提供了条件。通过原位插层聚合复合法制备了聚乙烯-MMT纳米复合材料(简称纳米复合材料)。用X射线衍射、场效应扫描电子显微镜和透射电子显微镜等技术考察MMT的层间距、纳米复合材料形态及MMT在聚乙烯基质中的分布时发现,MMT片层呈剥离状态。当纳米复合材料中MMT的质量分数为1.5%-2.0%时,纳米复合材料具有良好的力学性能。

Structure and Properties of Polyethylene-Montmorillonite Nano-Composites via In-Situ Polymerization

Polyethylene(PE)-montmorillonite(MMT)nano-composite was prepared by in-situ polymerization over MMT-MgCl2-TiCl4 intercalated catalyst.The catalyst was prepared by diffusing MgCl2 into butanol swollen MMT layers and then loading TiCl4 on inner/outer surfaces of MMT layers.Introduction of MgCl2 to MMT can reduce unfavorable effects of MMT surface on catalytic process and increase d-spacing between MMT layers,which provides space for Ti catalytic sites.Its introduction is also advantageous to interlamellar exfoliating of MMT during polymerization.The d-spacing between MMT layers,morphology of nano-composite and dispersion of MMT within PE were investigated by means of XRD,ESEM and TEM.Results show that MMT layers exfoliated from PE matrix.The impact and tensile properties of nano-composite were also measured.When content of MMT in nano-composite is 1.5% 2.0%(mass fraction),its mechanical properties are most favorable.