Influence of spacer groups on grafting ability, curing ability, and film properties of water-based radiation curable latexes

摘要

Film-forming polystyrene/poly(n-butyl acrylate-co-glycidyl methacrylate) [PS/P(BA-co-GMA)] core-shell latex particles were prepared via a two-stage emulsion polymerization procedure using a PS latex seed. A delayed addition of GMA was used to locate the functional epoxy groups near the surface of the particles. The surface-bound epoxy groups were used as grafting sites for unsaturated carboxyl functional monomers having the unsaturated groups and the carboxylic group separated by 1, 5, or 10 oxyethylene units. Grafting and curing characteristics and film properties after irradiation were investigated as a function of the number of oxyethylene units. A BA-GMA [P(BA-co-GMA)] copolymer was used as a model system for the core-shell latex particles for quantification of the grafting reactions. The grafting was demonstrated by FTIR and H-1-NMR spectroscopy. The effects of crosslinking was studied by thermal mechanical analysis and dynamical mechanical analysis. Differential photocalorimetry was also used for evaluation of the curing ability. It was demonstrated that the reagent having five oxyethylene units in the spacer group was grafted onto the polymer backbones to a larger extent than the other two reagents, and a more thoroughly cured film was obtained upon irradiation. (C) 1998 John Wiley & Sons, Inc. [References: 23]