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Preparation of poly(vinyl acetate) microspheres with narrow particle size distributions by low temperature suspension polymerization of vinyl acetate
Authors:Se Geun Lee  Jae Pil Kim  Ick Chan Kwon  Dong Soo Shin  Sung Soo Han  Won Seok Lyoo
Abstract:To estimate influences of suspension polymerization conditions including conversion, polymerization temperature, stirring rate, initiator concentration, monomer concentration, and suspending agent concentration on the volume average diameter (Davg) and particle size distribution (PSD) of poly(vinyl acetate) (PVAc) microspheres, vinyl acetate (VAc) was suspension‐polymerized at low temperature using 2,2′‐azobis(2,4‐dimethylvaleronitrile) as an initiator. The effects of each condition, on Davg of PVAc microspheres, were expressed as follows, Davg = conversion]atemperature]brpm]cADMVN]dVAc]f suspending agent]g. Logarithms of Davg were linearly proportional to those of polymerization conditions, and their exponents, a, b, c, d, f, and g were calculated as 0.27, ?13.7, ?1.37, ?0.21, 0.58, and 0.29, respectively. Variations of PSDs, according to polymerization conditions, were examined by considering polymerization rate, droplet or suspension viscosity, and droplet break‐up/coagulation equilibrium. From these results, PVAc microspheres with various sizes and narrow PSDs were obtained effectively under carefully controlled polymerization conditions, which can be used as promising precursors of novel PVA microspheres through heterogeneous surface saponification. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4064–4070, 2006
Keywords:suspension polymerization  PVAc  microspheres  narrow PSD
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