Morphology of latex particles formed by poly(methyl methacrylate)-seeded emulsion polymerization of styrene

Abstract

SynopsisPoly(methy1 methacrylatebpolystyrene composite particle latexes were prepared by poly(methy1 methacrylatehseeded emulsion polymerization of styrene employing batch, swelling-batch, and semibatch methods. The changes in particle morphology taking place during the polymerization reaction were followed by electron microscopy. Anchoring effect exerted by ionic terminal groups introduced by ionic initiator was found to be the main factor in controlling the particle morphology. The polymer particles obtained by oil-soluble hydrophobic initiators such as azobisisobutyronitrile and 4,4'-azobis44-cyanovaleric acid) gave the inverted core-shell morphology. Water-soluble hydrophilic initiator, K2&08, also gave the inverted coreshell morphology. However, in this case the occurrence of the halfmoonlike, the sandwichlike, and the core-shell morphologies were also observed depending upon the polymerization conditions. The distribution of terminal S O T groups on the surface area of polystyrene particles could be controlled by initiator concentration and polymerization temperature. Viscosity of polymerization loci dictated the movement of polymer molecules, thus causing the unevenness of particle shape and phase separation at high viscosity state. Viscosity was controlled by the styrene/poly(methyl methacrylate) ratio, the addition of a chain transfer agent or a solvent which is common to polystyrene and poly(methy1 methacrylate).

Morphology of poly(isoprene-co-styrene-co-methacrylic acid) latex prepared by two-stage seeded emulsion polymerization

“…8 ͚ 1566 be influenced by the initiator end groups, which may affect the morphology of the heterogeneous latex particles, as reported by Cho and Lee. 16 When hydrophilic monomers such as methacrylic ratios and using different monomer addition techor acrylic acid are used, as pointed out by these niques, i.e., seeded batch and semicontinuous polyauthors, the influence of terminal initiator end merizations. Osmium tetroxide (OsO 4 ) was used for groups on the morphology can be neglected.…”

N-Substituted Acrylamide-Styrene Copolymer Latices III. Morphology of Latex Particles

“…Particle morphology was controlled by the species and concentrations of initiators and the viscosity of polymerization loci in a poly-(MMA) seeded emulsion polymerization of St. 21 It was emphasized by the authors that the anchoring effect arising from terminal ionic groups is an important factor determining the particle morphology and an increase in the initiator concentration causes the formation of uneven-shaped particles.…”

Morphology, thermal property, and mechanical property of core-shell latex polymers. I. Effect of heating and pressuring on PBA/PS linear composite polymer

“…In recent years, many artimers, the surface tension, the molecular weight cles [1][2][3][4][5][6] studied the synthesis of composite latex or of the polymers, 11-13 the compatibility of the polylatex IPN to improve the degree of compatibility mers, 14 and the properties of the initiators. 15 between the two polymer phases. The effects of heating on the thermal and meBy the method of seeded emulsion polymerizachanical properties of a PBA/PS composite latex tion, a core-shell polymer/polymer composite lawere studied by Chen et al 16,17 They pointed out tex was synthesized.…”