Preparation of waterborne epoxy acrylate/silica sol hybrid materials and study of their UV curing behavior

A novel waterborne epoxy acrylate (WEA) was synthesized using bisphenol A epoxy resin as basic resin (E-44), acrylic acid (AA) and maleic anhydride (MA) as modification agent. Nano-silica sol was synthesized by a sol-gel method using tetraethyl orthosilicate (TEOS) as precursor. The UV curable waterborne epoxy acrylate/silica sol hybrid materials were prepared by UV radiation, in which the synthesized WEA served as an organic polymer phase, and the nano-silica sol as an inorganic phase. 3-Trimethoxysilyl-propyl methacrylate (TMSPM) was selected as a coupling agent between the organic polymer phase and the inorganic phase. The influence of the photoinitiator amount and the curing time on the curing degree of the mixture system was investigated, and both the WEA coated film and the hybrid material coated film were characterized by Fourier transform infrared (FT-IR) spectra and thermogravimetry (TG) analysis. The experimental results showed that the maximum curing degree achieved was 88% gel content, the optimal photoinitiator amount was 3.5%, and curing time was 40 s. FT-IR analysis implied that WEA/silica sol hybrid materials were formed for the hybrid between WEA and TMSPM modification silica sol. TG analysis indicated that the decomposition temperature of WEA/silica sol hybrid material coated film was 33 degrees C higher than that of WEA coated film, which indicated that the addition of nano-silica sol improved the thermal stability of waterborne epoxy acrylate (WEA). (C) 2010 Elsevier B.V. All rights reserved.