Sugar-Based Methacrylate Resins for Use in High-Performance, Transparent, and Sustainable Thermoset Coatings

This paper reports methacrylate resins incorporating biobased building blocks, synthesized using commercially available galactarate (GalX) and xylofuranose (IPrXF), modified with methacrylate groups through efficient transesterification. The study revealed that these biobased resins, GalX Me DMA and IPrXF DMA, cure at significantly lower temperatures (100–110 °C) compared to the commercial UMA 121 derived from urethane methacrylate containing methylene bisphenyl isocyanate building blocks. Thermal analysis showed that these cured resins exhibit exceptional thermostability, with an initial decomposition temperature exceeding 230 °C and a 50% weight loss temperature above 380 °C, outperforming UMA 121 thermosets. Mechanical testing using quantitative nanomechanical mapping with atomic force microscopy revealed elastic modulus values ranging from 2.9 to 3.8 GPa, which significantly outperforms previously published biobased thermosets and was closely comparable to UMA 121, which demonstrated an elastic modulus of 4.7 GPa. Pressure testing further corroborated these findings, confirming the robust mechanical performance of the biobased resins. The biobased resins exhibited remarkable enzymatic stability against degradation by polyester hydrolase PHL7 and demonstrated excellent resistance to chemical exposure. Notably, the sugar-based resins developed in this work contain a relatively high weight percentage of biobased components, reaching up to 70%. The biobased thermosets are transparent, colorless, and exhibit excellent film-forming properties. Overall, these resins offer promising performance for sustainable, durable coatings, combining high thermal stability, mechanical strength, and favorable environmental properties.