Synthesis and Curing Kinetics of UV-Curable Waterborne Bisphenol-S Epoxy-Acrylate/Polyurethane-Acrylate/Methylacryloylpropyl-POSS Nanocomposites

In order to prepare waterborne UV-curable polyurethane-acrylate (PUA) /epoxylacrylate (ERA) nanocomposites, the PUA, bisphenol-S epoxy acrylate (BPSEA) and methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) were synthesized. UV-curable BPSEA/PUA/MAP-POSS nanocomposites were prepared. The curing process, kinetics, and properties of the nanocomposites were investigated by Fourier transform infrared spectrometer (FTIR), differential scanning calorimeter (DSC) and dynamic mechanical analyzer (DMA). The base-acid resistance ability, adhesive strength, and hardness of coating films were determined. The results showed that these nanocomposites could be cured by both UV-light irradiation and a thermal free radical polymerization. Under the UV-light irradiation, they could be cured basically completely in about 20 min. The thermal free radical curing reaction could be described by a two-parameter autocatalytic. Sestak-Berggren (S-B) model. The dynamic mechanical loss peak temperature, T-p, of the cured nanocomposites increased with increasing MAP-POSS content up to 8 wt%, an enhancement of 5.8 degrees C over the pure BPSEA/PUA system, and then decreased. Films of the nanocomposites also had better base-acid resistance ability and hardness than pure BPSEA/PUA.