Renewable Myrcene-based UV-curable Monomer and its Copolymers with Acrylated Epoxidized Soybean Oil: Design, Preparation, and Characterization

An innovative myrcene-based ultraviolet curable vinyl ester monomer was synthesized, and its molecular structure was analyzed with Fourier transform infrared spectroscopy and nuclear magnetic resonance ((HNMR)-H-1 and (CNMR)-C-13) analysis. A series of copolymers were also prepared by mixing the myrcene-derived monomer with another vinyl ester monomer, acrylated epoxidized soybean oil, under ultraviolet light. The curing process was monitored using Fourier transform infrared spectroscopy. Ultraviolet curing analysis showed that all the mixed systems had high curing rates and were fully cured within the first 30 seconds. When the weight ratio of myrcene-derived monomer to acrylated epoxidized soybean oil was 50/50, the ultimate double bond conversion reached 94.08%. Dynamic mechanical analysis showed that the storage modulus and glass transition temperature of the cured resins both increased with increasing content of myrcene vinyl ester monomer because the molecular structure of myrcene-derived vinyl ester monomer was more rigid and stronger than that of acrylated epoxidized soybean oil. Thermogravimetric analysis indicated that the main thermal initial decomposition temperatures were all above 360 degrees C, demonstrating that the copolymers had modest thermal stability.