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High polymer/surfactant ratio in the seeded semicontinuous heterogeneous polymerization of vinyl acetate
Author(s) -
MartínezGutiérrez Hugo,
OvandoMedina Víctor M.,
Peralta René D.,
Mendizábal Eduardo,
Puig Jorge E.
Publication year - 2013
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.23453
Subject(s) - polymerization , emulsion polymerization , monomer , vinyl acetate , pulmonary surfactant , microemulsion , materials science , polymer chemistry , polymer , chemical engineering , copolymer , composite material , engineering
Vinyl acetate (VAc) was polymerized by a seeded semicontinuous heterogeneous process. Stable latexes with a polymer/surfactant weight ratio of 65 were obtained, which is comparable with the highest value reported in the literature for emulsion polymerization but with the advantage of obtaining smaller particles (average diameter, D p = 53 nm) which are similar to those obtained by microemulsion polymerization. The surfactant (sodium dodecylsulfate, SDS) concentration used in the recipe (0.32 wt%) is much lower than those typically used in microemulsion polymerization. Although molar masses increased during the continuous monomer addition period, they were small at the end of the reaction ( M n = 69 × 10 3 g·mol –1 ) and this was attributed to bimolecular termination inside the particles. The values of polymerization rate ( R p ) and monomer addition rate ( F m ) were nearly the same, indicating that polymerization was performed under monomer starved conditions. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers