片层硅酸盐用于热固性PU/PLS复合可能性探讨

高岭土(Kaolinite)和蒙脱土(Montromollite)等粘土，被广泛用作添加剂来改善聚合物的耐热性能。文章用各种先进技术对高岭土与蒙脱土的形态、组成和结构进行表征比较。电子透射电镜及电子探针(TEM/EDX)结果显示高岭土较蒙脱土有较大的粒径和较小的硅铝比，TEM还显示出这些粘土是由片层粒子堆积而成。热重分析(TGA)的结果表明蒙脱土由于失去吸附水从60 ℃升温至90 ℃失重明显(约7%)，而高岭土在此温度下几乎不失水。高岭土脱除结构羟基官能团脱水失重的温度大约在510 ℃，低于蒙脱土的670 ℃。室温下光声傅里叶变换(PAS-FTIR)红外光谱显示蒙脱土在羟基吸收区有较强的吸附水的吸收，1 650 cm-1处孤立的弱吸收谱带可给予左证。变温红外和TGA的结果显示，片层硅酸盐表面的结构羟基从100～500 ℃非常稳定，它可以和异氰酸酯基团(NCO)封端的预聚物反应形成热固性PU/PLS复合聚合物。

Implication of Structure for Nano Clays Used in Thermalsetting PU/PLS Composite

Clays such as kaolinite and montmorillonite, are commonly used as an additive to modify the thermal properties of polymer. In the present work, the morphology, composition, shape and structure of montmorillonite and kaolinite were characterized and compared by various advanced techniques. The TEM/EDX data showed that the kaolinite has a larger particle size and a lower Si/Al ratio than montmorillonite. These clays were stacked by platelets. The TGA results revealed that montmorillonite loses significant weight (around 7%) from 60 to 90 degrees C due to the dehydration of absorbed water, however, kaolinite almost doesn't lose weight in this temperature range. Kaolinites loses its weight because of the loss of its structural OH groups at a lower temperature (around 510 degrees C) than montmorillonite (670 degrees C). The PAS-FTIR spectra showed that montmorillnite has a strong absorbance of hydroxyl group in hydrogen bond region at room temperature, which presents a strong ability to adsorb water on its surface. The results of varied infrared temperature and TGA showed that their structural OH group is very stable from 100 to 500 degrees C, and it is possible to form thermosetting PU/PLS composite by reaction with the isocynate group of polyurethane prepolymer.