Nonisothermal shear-induced crystallization of polypropylene-based composite materials with montmorillonite
Nonisothermal shear-induced crystallization of polypropylene-based composite materials with montmorillonite
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DOI：
10.1016/j.eurpolymj.2013.04.029
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发表时间：
2013-08-01
影响因子：
6
通讯作者：
Gadzinowska, K.
中科院分区：
文献类型：
--
作者：
Szkudlarek, E.;Piorkowska, E.;Gadzinowska, K.
研究了有机改性蒙脱土（o-MMT）和剪切流动对等规聚丙烯（iPP）非等温结晶和结构显现的影响。iPP与3 wt.%的复合材料在143、153和163 ℃的不同温度下开始，在10 ℃ min（-1）冷却期间，以1 - 40 s（-1）的速率剪切o-MMT、与马来酸酐接枝的iPP相容的纳米复合材料和非相容的复合材料、iPP与相容剂和纯iPP的共混物10 s。在静态条件下，所有研究材料的结晶行为没有差异。然而，流动的影响，即结晶温度的增加，成核的增强和晶粒尺寸的减小，以及晶体的取向，虽然依赖于剪切温度和速率，被放大的o-MMT的存在。观察到最强的效果与剥离型粘土的增容纳米复合材料。在143 ℃下剪切的纳米复合材料中，结晶温度增加了16 ℃，对于共混物和非增容复合材料实现了超过12 ℃。然而，即使在后一种情况下，对于纯iPP测量的增加也大于7 ° C。剪切的纳米复合材料表现出α相晶体的取向，其中（040）晶面平行于剪切方向，并且（110）晶面双峰取向，平行于和垂直于剪切方向。(C)2013爱思唯尔有限公司保留所有权利。
A combined effect of organo-modified montmorillonite (o-MMT) and shear flow on nonisothermal crystallization and emerging structure of isotactic polypropylene (iPP) was studied. Composite materials of iPP with 3 wt.% of o-MMT, nanocomposite compatibilized with maleic anhydride grafted iPP and non-compatibilized composite, blend of iPP with the compatibilizer and neat iPP were sheared for 10 s at a rate ranging from 1 to 40 s(-1) during cooling at 10 degrees C min(-1), beginning at different temperatures: 143, 153 and 163 degrees C. The crystallization behavior of all the materials studied did not differ under quiescent conditions. However, the effects of flow, that is an increase of crystallization temperature, enhancement of nucleation and decrease of grain size, and also orientation of crystals, although dependent on shear temperature and rate, were amplified by the presence of o-MMT. The strongest effects were observed for the compatibilized nanocomposite with exfoliated clay. In the nanocomposite sheared at 143 degrees C crystallization temperature increased by 16 degrees C, more than 12 degrees C achieved for the blend and the non-compatibilized composite. However, even in the latter case the increase was larger than 7 degrees C measured for neat iPP. The sheared nanocomposite exhibited the orientation of alpha-phase crystals with (040) crystallographic planes parallel to the shearing direction and (1 1 0) planes bimodally oriented, parallel and normal to the shearing direction. (C) 2013 Elsevier Ltd. All rights reserved.