原位分散聚合制备聚甲基丙烯酸甲酯/超细碳酸钙复合粒子

Preparation of Poly(methyl methacrylate)/Ultrafine CaCO3 Composite Particles by in-situ Dispersion Polymerization

为了提高聚合物在超细碳酸钙粒子表面的接枝和包覆,对超细碳酸钙锚固偶氮引发剂及甲基丙烯酸甲酯(MMA)/改性碳酸钙原位分散聚合进行了研究。碳酸钙粒子经氨基硅烷偶联剂处理后能与偶氮二氰基戊酸反应而实现锚固化,由红外光谱和元素分析证明了偶联和锚固反应。通过锚固在碳酸钙上的偶氮引发剂的引发作用,由MMA分散聚合制备了聚甲基丙烯酸甲酯(PMMA)接枝率高的PMMA/超细碳酸钙复合粒子,PMMA接枝率随聚合转化率增加而增加,而接枝效率随之降低;接枝PMMA的碳酸钙粒子在四氢呋喃和MMA中的分散稳定性明显优于未改性碳酸钙。

In order to improve the grafting and coating of polymer on ultrafine CaCO3 particles, the anchoring of 4,4＇-azobis（4-cyanopentanoic acid） （ACPA） onto ultrafine CaCO3, and dispersion polymerization of methyl methacrylate （MMA） in the presence of CaCO3 anchored with azo initiator were investigated. CaCO3 was treated with 3-aminopropyltriethoxysilane at first, followed by the condensation reaction with the hydroxy group of ACPA. The coupling and anchoring reactions are confirmed by infrared spectrum and element analysis. The rate of MMA dispersion polymerization increases with the amount of ACPA anchored on CaCO3, but the initiation efficiency of anchored ACPA is lower than that of free ACPA in polymerization. The grafting of PMMA on CaCO3 is also confirmed by infrared spectrum. It shows that the grafting ratio of PMMA increases with the polymerization conversion, while the grafting efficiency of PMMA decreases. The amount of anchored ACPA has no significant influence on the grafting efficiency of PMMA. PMMA/CaCO3 composite particles with higher PMMA grafting degree could be prepared by in-situ dispersion polymerization initiated by ACPA anchored on CaCO3. The dispersion stability of CaCO3 grafted with PMMA in MMA and tetrahydrofuran is significantly improved in comparison with that of unmodified CaCO3.