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Effect of Nanoclay on Styrene and Butyl Acrylate AGET ATRP in Miniemulsion: Study of Nucleation Type, Kinetics, and Polymerization Control
Author(s) -
Hatami Leila,
HaddadiAsl Vahid,
AhmadianAlam Leila,
RoghaniMamaqani Hossein,
SalamiKalajahi Mehdi
Publication year - 2013
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20757
Subject(s) - miniemulsion , polymerization , polymer chemistry , chemistry , styrene , dispersity , atom transfer radical polymerization , acrylate , micelle , radical polymerization , butyl acrylate , molar mass distribution , copolymer , chemical engineering , polymer , organic chemistry , aqueous solution , engineering
ABSTRACT Poly(styrene‐ co ‐butyl acrylate)/clay nanocomposites were synthesized in miniemulsion via activators generated by electron transfer (AGET) for atom transfer radical polymerization (ATRP). Optimum amounts of catalyst and reducing agent were chosen by considering a linear increase in ln([M 0 ]/[M]) versus time, narrow molecular distribution, and low polydispersity index (PDI). Critical micelle concentration and cross‐sectional surface area per surfactant head group were determined by surface tension analysis. Calculations show that droplet nucleation is the dominant mechanism of nucleation in a miniemulsion system, and there is no micelle in the system. Gel permeation chromatography was used to characterize molecular weight, PDI, and molecular weight distribution. After determination of appropriate conditions, poly(styrene‐ co ‐butyl acrylate)/clay nanocomposite latexes were synthesized. Low PDI, narrow molecular weights, and first‐order kinetics of the nanocomposites justify that polymerization is well controlled. Kinetics of polymerization decreases by clay loading. The apparent propagation rate constant ( k app ) of polymerization in the case of poly(styrene‐ co ‐butyl acrylate) is 4.079 × 10 −6 , which becomes 0.558 × 10 −6 in the case of poly(styrene‐ co ‐butyl acrylate)/clay nanocomposite with 2% nanoclay. A decrease in the polymerization rate is related to the hindrance effect of nanoclay layers on monomer diffusion toward the loci of growing macroradicals.