Fabrication of Nano-SiO_2 Initiator by a Novel Room Temperature Esterification Method and In-situ Polymerization
新型室温酯化法制备纳米SiO2引发剂和原位引发聚合

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.