纳米碳酸钙表面原位聚合聚甲基丙烯酸甲酯微结构及性能

Microstructure and Properties of Poly(methyl methacrylate) Coated on the Surface of Calcium Carbonate Nanopaticles by in-situ Polymerization

利用原位乳液聚合在纳米碳酸钙(CaCO3)粒子表面接枝包覆了聚甲基丙烯酸甲酯(PM-MA),借助于FT IR1、H-NMR、TGA和GPC等手段研究了PMMA界面层结构、热稳定性及分子量分布。结果表明:纳米CaCO3粒子表面接枝的PMMA以间同(rr)立构结构为主,其含量约52.8%;热稳定性介于无皂和有皂乳液聚合之间,热分解温度比无皂乳液聚合的PMMA高约50°C,其分解主要由PMMA亚乙烯基链端的β-断裂及自由链断裂引起。纳米碳酸钙表面接枝的PM-MA分子量比均聚物大,分布也较宽。纳米CaCO3粒子的存在对PMMA的微结构没有影响,但对PMMA的热稳定性、分子量及其分布有影响。

The microstructure, thermal properties, and molecule weight and its distribution of PMMA coated on the surface CaCO3 nanoparticles by in-situ emulsion polymerization were studied by FTIR,^1H-NMR, TG and GPC. The results indicate that the main tacticity of PMMA which coated on the surface of CaCO3 nanoparticles is syndiotactic （rr）, and its content is about 52, 8%. The thermal decomposition temperature of coated PMMA is between that of PMMA prepared by emulsifier-free emulsion polymerization and PMMA by emulsion polymerization with emulsifier, and is higher about 50℃ than that by emulsifier-free emulsion polymerization. The molecular weight of coated PMMA is higher than that of PMMA homopolymerized, and its polydispersity is wider than that of PMMA homopolymerized. The presence of CaCO3 nanoparticles affects only on the thermal properties and its molecular weight distribution but not on the microstructure of PMMA.