累托石粘土/热塑性聚氨酯弹性体纳米复合材料的热性能研究

以十二烷基季铵盐与累托石 (REC)进行阳离子交换得到有机粘土 (OREC) ,以OREC与热塑性聚氨酯弹性体 (TPUR)采用熔融挤出共混法制备了OREC TPUR纳米复合材料 .用透射电子显微镜 (TEM)表征了复合材料的微相结构 ,测试了复合材料动态热机械性能 (DMA)及热失重 (TG) ,讨论了复合材料的耐热空气老化性能及耐油介质性能等 .结果表明 ,累托石粘土在聚氨酯热塑性弹性体中以纳米尺寸分散 ,纳米复合材料具有较高的动态热机械性能 ,其储能模量最大可提高 7倍多 ,损耗模量最大可提高 4倍多 .复合材料的其他性能均有不同程度的提高 ,特别是OREC添加量为 2 %时 ,复合材料TG、耐油性及耐空气老化性能最高 .其初始分解温度提高 1 5℃ ,在 40 #机油中浸泡 1 68h后拉伸强度保持率达到 86 4% ,1 2 0℃热空气老化箱中老化 72h后拉伸强度保持率达到 87 0 % .

THE THERMAL PROPERTIES OF RECTORITE/THERMOPLASTIC POLYURETHANE NANOCOMPOSITES

OREC (organic rectorite clay)/TPUR(thermoplastic polyurethane) nanocomposites were prepared via melt blending.There were four temperature ranges in the extruder.The temperature was 120℃ at the extruder head,and was 130℃,140℃ and 120℃ in the former,middle and back parts,respectively.OREC was prepared with natural rectorite and dodecanic quaternary ammonium salt through ion-exchange.The nanoscale dispersibility of the OREC layers in the TPUR matrix was revealed by using transmission electron microscopy (TEM).The thermodynamic mechanical analysis (DMA),thermogravimeric analysis(TG),oil-resistant and hot air aging of nanocomposites were also measured. The results showed that the largest storage modulus is 7 times more than that of pure TPUR's,and the largest loss moduli is 4 times more than that of pure TPUR's.The other thermal properties of the composites have been enhanced as compared with those of the TPUR matrix due to the well-dispersed OREC layered particles in the OREC/TPUR nanocomposites.When the content of OREC is 2%,the initial degradation temperature of the composite is 15℃ higher than that of the pure TPUR,and the ratio of the residual tensile strength to the original strength is over 86% after oil treatment for 168 h,or air aging at 120℃ for 72 h.