An emerging liquid thermoplastic resin based structural composite through VARTM: a comprehensive comparison of the mechanical performance with conventional epoxy based composites at ambient and elevated temperature

Over the past few decades, thermoset-based fibrous composites have proven to be a superior alternative to metals in structural applications. Thermosets, especially epoxy-based FRP composites, have widespread acceptance due to their ease in fabrication along with excellent strength-to-weight ratio, chemical resistance, and minimal environmental impact. However, in the era of sustainability, extensive application of thermoset-based FRP composites is limited due to their poor recyclability, which poses an environmental threat. To address this issue, thermoplastic matrix-based composites present a promising alternative. Typically, thermoplastic matrices are available in pellet or sheet form, requiring high temperature processing which complicates the fabrication process. To overcome these challenges, a new liquid, Methyl Methacrylate (MMA)-based Liquid Thermoplastic Resin (LTR), has recently been developed. This study systematically evaluates LTR based glass fibre composite (GF/LTR) in various mechanical properties, including flexural strength, interlaminar fracture toughness, and interlaminar shear strength at different temperatures, and compares it with conventional epoxy based glass fibre composite (GF/Epoxy). The VARTM process was used to fabricate both the composites. In every assessment, GF/LTR outperformed GF/Epoxy composites, such as in flexural test at 30℃ GF/LTR composite exhibited 18% higher performance compared to the GF/Epoxy composites. Also, the fracture toughness of GF/LTR shows an improvement of approximately 27.5% at 30℃ and 36.5% at 50 °C, over GF/Epoxy, highlighting the superior fibre-matrix interaction and cohesive integrity in composite LTR. Additionally, fractographic analysis was conducted to gain insights into the failure modes of GF/LTR composites.