聚甲基丙烯酸甲酯包覆纳米SiO_2表面的聚合反应研究

Study of radical grafting polymerization for encapsulation of nano-SiO_2 surface with polymethylmethacrylate

通过表面接枝的方法,在室温下用偶联剂(MPS)KH-570对纳米SiO2进行接枝,经引发剂引发甲基丙烯酸甲酯(MMA)发生自由基聚合包覆,并通过TEM和FTIR等测试手段表征粉体有机包覆层的形貌和化学组成结构,应用DSC和TGA等测试方法研究了反应条件对复合粒子结构和性能的影响.为了得到较高的接枝率,用两种不同浓度的偶联剂对纳米SiO2进行预处理,纳米SiO2-MPS复合粒子的接枝率随着偶联剂浓度的增大而提高,且SiO2-MPS-PMMA复合粒子的接枝率和单体的转化率随着引发剂的浓度和单体的浓度的增大而明显提高.

By using surface grafting method, the nano-SiO2 was grafted first with couplant（MPS） KH-570 at room-temperature and then encapsulated with free-radical polymerization of polymethylmethacrylate initiated by initiator. The morphology and chemical composition and microstructure of the organic encapsulation in the form of powdery layer were characterized by means of TEM and FTIR testing. The influence of reactionary conditions on microstructure and characteristics of the composite particle was studed with DSC and TGA testing, also. In order to obtain greater grafting rate, the nano-SiO2 was pre-processed with two couplants of different concentration. It was found that the grafting rate of nano-SiO2-MPS composite particles was increased with the concentration of couplant. Besides, the grafting rate of SiO2-MPS-PMMA composite particles as well as the convesive rate of monomers were remarkably increased with the concentrations of both the initiator and monomers.