Enhancing Toughness and Water Resistance of UV-Curable Acrylate Resins via Modification with Isobornyl Acrylate

This study aims to improve the toughness and water resistance of light-curable acrylic resins while maintaining a well-balanced combination of thermal stability, mechanical performance, and crosslinking density. To achieve this goal, a tailored molecular architecture was designed using methyl methacrylate (MMA) and butyl acrylate (BA) as primary monomers, with glycidyl methacrylate (GMA) and isobornyl acrylate (IBOA) incorporated as functional comonomers. A modified epoxy acrylate prepolymer was synthesized and further functionalized via post-polymerization grafting with acrylic acid (AA). This approach enabled the successful preparation of IBOA-modified UV-curable unsaturated acrylate prepolymers (designated MEA-0 to MEA-4) and their corresponding cured films. The thermal, mechanical, and water-resistance properties of the resulting films were systematically evaluated using FT-IR, DTG, DSC, and DMA analyses. The results indicate that precise modulation of the IBOA content effectively compensates for the reduction in tensile strength caused by lower crosslink density, while simultaneously achieving substantial improvements in elongation at break and fracture energy. Compared to unmodified acrylate systems, water absorption was significantly reduced from 13.05% to 2.13%. Furthermore, the modified materials exhibited excellent adhesion to polypropylene substrates. Notably, the incorporation of IBOA ester groups did not adversely affect thermal resistance, demonstrating that the integration of IBOA moieties into the acrylic side-chain structure markedly enhances the overall performance of the crosslinked network. Accordingly, this work presents an efficient and versatile molecular design strategy for developing high-performance, light-curable unsaturated polyacrylate systems with optimized multifunctional properties.