Study on Toughening of In Situ Polymerized Poly(Methyl Methacrylate) Resin for Liquid Composite Molding Technology

In situ polymerized poly(methyl methacrylate) resin, a liquid molding thermoplastic, offers advantages such as low cost, recyclability, and environmental friendliness. However, its poor toughness limits its application potential. This study proposes a toughening method for poly(methyl methacrylate) resin used in liquid molding by copolymerizing it with butyl acrylate (BA) and butyl methacrylate (BMA) monomers. The effects of BA or BMA on the polymerization reaction and mechanical properties were investigated, with a focus on improving toughness. Dynamic thermal analysis (DSC) and 13 C NMR spectroscopy confirmed the formation of copolymers and the incorporation of BA or BMA monomers. The introduction of BA or BMA lowered the glass transition temperature but had minimal impact on the polymerization rate, with only a slight increase in polymerization time (14.77‰ and 4.320‰ for 8% BA or BMA, respectively). Adding small amounts of BA or BMA significantly enhanced the toughness of the resin. When the content reached 4%, elongation at break increased by 103% and 139%, and impact strength improved by 222% and 328%. These results shift the failure mode from brittle to ductile fracture, paving the way for the industrial application of high-performance in situ polymerized poly(methyl methacrylate) resin.