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

Daisuke Nagao, Takuya Ueno, Daisuke Oda, Mikio Konno

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1051-1056
Number of pages6
JournalColloid and Polymer Science
Volume287
Issue number9
DOIs
Publication statusPublished - 2009 Sep 1

Keywords

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

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry
  • Colloid and Surface Chemistry

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