INFLUENCE OF SPACER GROUPS ON GRAFTING ABILITY, CURING ABILITY, AND FILM PROPERTIES OF WATER-BASED RADIATION CURABLE LATEXES

Film-forming polystyrene/poly(n-butyl acrylate-co-glycidyl methacrylat e) [PS/P(BA-co-GMA)] core-shell latex particles were prepared via a tw o-stage emulsion polymerization procedure using a PS latex seed. A del ayed addition of GMA was used to locate the functional epoxy groups ne ar the surface of the particles. The surface-bound epoxy groups were u sed as grafting sites for unsaturated carboxyl functional monomers hav ing 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 n umber of oxyethylene units. A BA-GMA [P(BA-co-GMA)] copolymer was used as a model system for the core-shell latex particles for quantificati on of the grafting reactions. The grafting was demonstrated by FTIR an d H-1-NMR spectroscopy. The effects of crosslinking was studied by the rmal mechanical analysis and dynamical mechanical analysis. Differenti al photocalorimetry was also used for evaluation of the curing ability . It was demonstrated that the reagent having five oxyethylene units i n the spacer group was grafted onto the polymer backbones to a larger extent than the other two reagents, and a more thoroughly cured film w as obtained upon irradiation. (C) 1998 John Wiley & Sons, Inc.