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Synthesis of SBR/PMMA core/shell latices: The role of initiator and surfactant on particle morphology and instability performance
Author(s) -
Moghbeli M. R.,
Mohammadi N.,
Bagheri R.
Publication year - 2007
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.26286
Subject(s) - emulsion polymerization , polymer chemistry , chemical engineering , pulmonary surfactant , materials science , ammonium persulfate , particle (ecology) , electrolyte , styrene , surface energy , polymerization , chemistry , copolymer , composite material , polymer , oceanography , electrode , engineering , geology
Poly(butadiene‐stat‐styrene)/poly(methylmetacrylate), SBR/PMMA, structural latices were synthesized by using equal moles of different kinds of surfactants: anionic, nonionic, and anionic/nonionic mixture in a two‐stage emulsion polymerization. The results indicate that the application of anionic surfactants for the first stage, accompanying sodium persulfate initiator, KPS, for both stages led to core/shell and raspberry morphologies depended upon the hydrophilic lipophilic balance (HLB) of the surfactant. On the other hand, a core/shell structure was observed for structural latices which were synthesized via application of nonionic or anionic/nonionic mixed surfactants along with azobisisobutyronitrile, AIBN, and KPS as first and second‐stage initiators, respectively. The surface polarity and wettability of the seed particles and finally the tendency of the systems to gain the minimum surface free energy change are the basis for the observed morphologies. On the other hand, the stability of core/shell particles was investigated via incremental addition of an electrolyte, ammonium acetate, at temperature close to the glass transition of PMMA shell, 85°C. The particle size measurement on destabilized samples showed that the core/shell latex only stabilized by anionic surfactant was considerabely microagglomerated with increasing the electrolyte content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007