聚丙烯/蒙脱土纳米复合材料的等温结晶研究

ISOTHERMAL CRYSTALLIZATION KINETICS OF POLYPROPYLENE/ MONTMORILLONITE NANOCOMPOSITES

采用差示扫描量热法 (DSC)对插层聚合法制备的聚丙烯 /蒙脱土纳米复合材料 (PP MMT)的等温结晶过程进行了研究 .引入蒙脱土 (MMT)后 ,PP MMT的结晶速率大幅度提高 ,相对结晶度略有下降 .采用Avrami方程对结晶动力学进行研究 ,Avrami指数n≈ 3 .0 ,半结晶时间t1 2 大幅度降低 .采用Hoffman理论计算了PP MMT的球晶生长的单位面积表面自由能σe,结果表明σe

The isothermal crystallization kinetics of intercalatively polymerized polypropylene/montmorillonite (PP/ MMT) nanocomposites and isotactic polypropylene (PP) was investigated by differential scanning calorimetry (DSC). The relative crystallization degree of PP/MMT nanocomposites was decreased slightly after introducing montmorillonite. The isothermal crystallization process was described by the Avrami equation with exponent n approximate to 2.4 for pure PP and n approximate to 3.0 for PP/MMT nanocomposites. The half crystallization time (t(1/2)) of PP/MMT was much shorter than that of pure PP. The sigma (e), interfacial free energy per unit area perpendicular to PP chains, of PP/MMT. nanocomposites was calculated by Hoffman theory. The result showed that the sigma (e) was decreased with increasing the MMT content.