Size control of polystyrene nodules formed on silica particles in soap-free emulsion polymerization with amphoteric initiator |
| |
Authors: | Daisuke Nagao Takuya Ueno Daisuke Oda Mikio Konno |
| |
Institution: | (1) Department of Chemical Engineering, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai 980-8579, Japan |
| |
Abstract: | An amphoteric initiator of 2,2′-azobisN-(2-carboxyethyl)-2-2-methylpropionamidine] (VA-057) was applied to fabrication of raspberry-shaped composite particles in
soap-free emulsion polymerization of styrene in the presence of silica particles surface-modified with 3-methacryoxypropyltrimethoxysilane.
In the polymerizations, pH of the solution was ranged from 7.9 to 9.9 to alter dissociation degree of ionizable groups in
the initiator. Raspberry-shaped particles were obtained in a pH range of 8.0 to 9.3 followed by a tendency in which average
size of polystyrene (PSt) nodules adsorbed onto the silica particles decreased with pH. This tendency was similar to that
of polymer particles formed in conventional soap-free emulsion polymerization in the absence of the silica particles. An increase
in silica particle concentration led to a decrease in the final size in PSt nodules. The decrease was caused by the stabilization
of polymer particles fixed to the silica surface against polymer particle aggregation in water phase. |
| |
Keywords: | Amphoteric initiator Composite particle Polystyrene Raspberry-shaped Silica |
本文献已被 SpringerLink 等数据库收录! |