新型室温酯化法制备纳米SiO_2引发剂和原位引发聚合

Fabrication of Nano-SiO_2 Initiator by a Novel Room Temperature Esterification Method and In-situ Polymerization

提出了一种在室温、潮湿和大气环境等温和条件下,通过酯化反应在纳米SiO_2微球表面接枝偶氮分子,合成纳米SiO_2引发剂的新方法。使用这种纳米SiO_2引发剂原位引发单体苯乙烯和甲基丙烯酸甲酯进行自由基聚合,在SiO_2表面接枝聚苯乙烯或聚甲基丙烯酸甲酯。结果表明:用合成的纳米SiO_2引发剂原位引发单体聚合后,在纳米SiO_2表面接枝的聚合物约占SiO_2质量的45%;接枝聚合物后体系的平均粒径从80 nm增大到大约100 nm,得到了以SiO_2为核、以聚合物为壳的无机/有机复合微球。

A novel method for grafting azo-groups onto the surface of SiO2 nanoparticles to prepare SiO2-initiator by the esterification reaction under the mild conditions, has been developed. The monomers as styrene or methyl methacrylate was polymerized using azo-group bounded SiO2 as an initiator, and then polystyrene or poly（methyl methacrylate） chains grow out of the surface of SiO2 nanoparticles. Results show that polymer grafted onto the surface of SiO2 nanoparticles accounts of ca. 45% （mass fraction）of SiO2. As a result, the average particle size increases from 80 nm to 100 nm upon the polymer grafting. Consequently, the core-shell composite particles with polymer on the outside and SiO2 in the core are obtained.