不同工艺制备的PP/蒙脱土纳米复合材料的性能

选择一种新型有机蒙脱土（MMT），分别通过直接注塑法和挤出一注射法（简称挤出法）将聚丙烯（PP）与有机MMT复合，制备出高抗冲PP／MMT纳米复合材料。透射电子显微镜观察表明。挤出法制备的复合材料为全插层型结构，MMT分散均匀，尺寸小；而直接注塑法制备的复合材料为部分插层型结构．MMT明显分散不均匀，尺寸较大，且有少量团聚产生。力学性能测试表明，随着MMT的增加．2种试样的缺口冲击强度都有显著提高，均在ω（MMT）为4％时达到极大值。此时，挤出法试样缺口冲击强度比纯PP提高102％。屈服拉伸强度、弹性模量也略有提高；直接注塑法试样的缺口冲击强度比纯PP提高82．6％，但屈服拉伸强度、弹性模量都明显降低。

Properties of polypropylene/montmorillonite nanocomposites prepared with different molding processes

Two types of polypropylene/montmorillonite (PP/MMT) nanocomposites having high impact strength were prepared with a novel MMT via process of direct injection molding and melt extrusion-injection molding,respectively. The observation with transmission electron microscope (TEM) reveals that the nanocomposite prepared in extrusion-injection process features a structure with entire intercalation of MMT, which isdispersed homogeneously and present in smaller size inside the matrix; whereas the nanocomposite made in direct injection process exhibits a structure with partial intercalation of MMT, which exist in larger particle size and agglomerate in a given quantity. The mechanical tests indicate that the notched impact strength of the 2 nanocomposites increase significantly with MMT content and attain its maximum when mass fraction of MMT reaches 4%. Compared with pure PP reference, the notched impact strength of the specimen prepared in extrusion-injection process is increased by 102% and at the same time, its tensile strength at yield, at break and elastic modulus also rise somewhat. Under the same conditions, the notched impact strength of the specimen prepared in direct injection process is increased by 82.6%, while its tensile strength at yield, and elastic modulus lower apparently.