阳离子表面活性剂为乳化剂原位乳液聚合制备PS/MMT纳米复合材料

针对原位乳液聚合法制备聚合物/蒙脱土(MM T)纳米复合材料,为了实现蒙脱土片层的有机化处理和纳米复合材料的形成一步完成,以十六烷基三甲基溴化铵为乳化剂原位乳液聚合制备了PS/MM T纳米复合材料。XRD、FT-IR、TEM等分析表明,聚苯乙烯已插层进入蒙脱土的层间。在制备过程中,CTAB既充当了乳化剂,又充当了蒙脱土的插层处理剂,促进了苯乙烯在蒙脱土层间的聚合,同时也造成了蒙脱土片层一定程度的聚并。DSC分析表明,复合物的玻璃化转变温度有一定程度的提高。另外,还对蒙脱土存在下乳液聚合的特点进行了研究,发现MM T片层对乳液聚合的影响仅在聚合反应的初始阶段,使聚合速率有所下降,而对反应的后期阶段和反应产物的分子量影响不大。

PS/MMT NANOCOMPOSITE PREPARED BY IN SITU EMULSION POLYMERIZATION WITH CATIONIC SURFACTANT AS EMUSIFIER

In order to realize that the formation of nanocomposite and modification of montmorillonite can be completed in one step,PS/MMT nanocomposites were synthesized via in situ emulsion polymerization using cetyl trimethylammonium bromide(CTAB) as emulsifier.The structure of montmorillonite and nanocomposites were characterized by XRD,FT-IR and TEM,The results indicate that molecular chains of polystyrene have been intercalated into the galleries of montmorillonite and intercalated nanocomposites are formed.The distance between layers of montmorillonite in nanocomposite is bigger than that of nanocomposite prepared by emulsion polymerization using anion emulsifier,which demonstrate that the cationic surfactant CTAB acts as the emulsifier and also as an intercalated agent,facilitating the intercalation of polystyrene chains.The DSC curves indicate that the glass transition temperature of the nanocomposites is enhanced in some degree.The character of cationic emulsion polymerization in present of montamorillonite was also determined.The results show that the presence of montmorillonite decreases the polymerization rate during the initial stages,but the molecular weight of the products are similar.