Sustainable and Highly Efficient Synthesis of Reactive Diluents from Renewable Sources for Property-Enhancing Purposes in Glass-Containing Material Composites

Biobased reactive diluents are an alternative to fossil-based compounds, such as styrene, used in industrial-scale manufacturing. We proposed a more scalable, sustainable, and applicable synthesis of methacrylated biobased monomers involving a cheap and affordable catalyst, potassium acetate, as a substitute for the currently used 4-dimethylaminopyridine (DMAP). Also, the isolation of the formed byproduct during the synthesis, methacrylic acid, is involved in the introduced approach to reduce disposal waste and increase the production process's scalability. The synthesized biobased monomers based on vanillin, cinnamyl alcohol, vanillyl alcohol, and isosorbide were characterized via NMR, ESI-MS, and FTIR structural-verifying cross-analysis. We investigated all produced reactive diluents' rheological profiles, reactivity, and thermomechanical properties. Glass-containing composites were fabricated using the synthesized reactive diluents instead of the commercially applied styrene. The best-performing material, vanillin methacrylate (V-Mono MMA), reached a viscosity (η) of 621 mPa·s at 30 °C, a storage modulus (<i>E</i>') of 2450 MPa at 45 °C, a glass transition temperature (<i>T</i> _g) of 130.4 °C, a heat-resistant index (<i>T</i> _S) of 149.7 °C, a flexural modulus (<i>E</i> _t) of 41.4 ± 1.2 GPa, a flexural strength (σ_fM) of 1201.8 ± 54.3 MPa, and an interlaminar shear strength (σ_sbs) of 52.12 ± 0.6 MPa.