Size control of polystyrene nodules formed on silica particles in soap-free emulsion polymerization with amphoteric initiator

作者：Nagao Daisuke; Ueno Takuya; Oda Daisuke; Konno Mikio^*

来源：Colloid and Polymer Science, 2009, 287(9): 1051-1056.

DOI：10.1007/s00396-009-2063-7

• Amphoteric initiator
• Composite particle
• Polystyrene
• Raspberry-shaped
• Silica

An amphoteric initiator of 2,2'-azobis[N-(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.

• 出版日期2009-9