Reaction kinetics and microgel particle size characterization of ultraviolet-curing unsaturated polyester acrylates

摘要

The free-radical reaction kinetics and microgel formation of UV-curing unsaturated polyester acrylates were studied in terms of the effects of internal maleic and terminal acrylate unsaturations. A triacrylate-functional monomer, trimethylolpropane triacrylate, was used as the reactive diluent. A time-resolved Fourier transform infrared technique was used to evaluate the consumption of double bonds and showed that internal (maleic) double bonds were involved in microgel formation at a rate similar to that of the more reactive terminal (acrylic) double bonds. Dynamic light scattering was used to measure the microgel particle size. The introduction of internal unsaturations caused smaller microgels, whereas terminal acrylate unsaturations resulted in larger particle sizes. These results were attributed to the higher tendency of the internal maleic double bonds toward intramolecular cyclization reactions. (c) 2006 Wiley Periodicals, Inc.