星型POSS/PMMA复合材料的ATRP合成及其热性能研究

以γ-氯丙基三乙氧基硅烷为原料合成八官能团γ-氯丙基多面体低聚倍半硅氧烷(POSS),以该POSS为引发剂,通过原子转移自由基聚合(ATRP)合成具有星型结构的POSS/PMMA复合材料.通过傅立叶红外(FTIR)、核磁共振(NMR)、凝胶渗透色谱(GPC)和X-射线衍射(XRD)等手段对POSS和POSS/PMMA的化学组成和结构进行了表征,结果表明已经合成八官能团γ-氯丙基POSS,POSS/PMMA复合材料具有分子设计的预定结构,且复合材料的分子结构得到了较好的控制.通过ATRP法实现了POSS在聚合物中的单分散.此外,TGA的研究表明,POSS的引入提高了聚合物的热稳定性.

ATOM TRANSFER RADICAL POLYMERIZATION AND THERMAL PROPERTIES OF A STAR-SHAPED POSS/PMMA COMPOSITE

A star-shaped poly ( methyl methacrylate) with polyhedral oligoraeric silsesquioxane ( POSS) as a core was synthesized by atom thansfer radical polymerization (ATRP) , using octa(γ-chloropropyl) POSS as a initiator and CuCl/2,2'-bipyridine as catalyst system. Octa(γ-chloropropyl) POSS was prepared in methanol through the hydrolysis and condensation of γ-chloropropyltriethoxysilane, and a yield of 28% was obtained. The well-defined structures of POSS and POSS/PMMA composite were fully characterized by FTIR,NMR,GPC and XRD, with results showing POSS molecule was successfully formed, and the mono-dispersion of POSS was achieved by ATRP, meaning that there was only one POSS molecule in a polymer chain. The polydispersity indices (PDI) of POSS/PMMA composite with different polymerization time were 1. 20 and 1. 14,according to the measurement of GPC. The TGA results indicated the thermal stability of POSS/PMMA composite enhanced from 281℃ to 303℃ with the increase of POSS content, which was due to the incorporation of POSS molecules.