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Preparation of core–shell particles by dispersion polymerization with a poly(ethylene oxide) macroazoinitiator
Author(s) -
Kimoto Masaki,
Yamamoto Kazuhiko,
Hioki Ayako,
Inoue Youtaro
Publication year - 2008
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.28548
Subject(s) - ethylene oxide , materials science , copolymer , polymer chemistry , methyl methacrylate , polymer , monomer , polymerization , chemical engineering , colloid , poly(methyl methacrylate) , particle (ecology) , dispersion polymerization , composite material , oceanography , engineering , geology
A macroazoinitiator (MAI) containing a poly(ethylene oxide) (PEO) block was used with a methyl methacrylate monomer to prepare polymer particles in ethanol/H 2 O solutions. The effects of the monomer/MAI ratio (RMI) and H 2 O content in the solutions on the molecular weight, particle diameters, and chemical structure of the resulting polymer particles were investigated. The reaction mixtures showed three kinds of states, which were milky colloid solutions, macrogels and/or precipitations, and clear solutions. The colloid solutions were obtained in the solutions with an H 2 O content of about 50–90 vol % and a RMI of 20–400. In the colloid solutions, core–shell nanospheres consisting of PEO shells and poly(methyl methacrylate) (PMMA) cores were predominantly obtained. In the specific conditions close to the area of gel and/or precipitation formation, particles connected about 0.5–5 μm in length were obtained. Multiblock copolymers nanospheres tended to be obtained with lower RMIs, and PMMA‐PEO‐PMMA tri‐bloc and/or PMMA‐PEO di‐block copolymer nanospheres were obtained with higher RMIs. The solubility of the monomer and the generated polymer in solutions may have affected the polymerization development and the state of the products. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008