Acryloyl-group functionalized graphene for enhancing thermal and mechanical properties of acrylated epoxidized soybean oil UV-curable based coatings

Abstract

Abstract Recently, acrylate epoxidized soybean oil (AESO) has become one of the most important industrial, bio-based, UV-curable resins. To reinforce AESO-based UV-curable coatings, acryloyl-group functionalized graphene (acr-RGO) was successfully prepared and characterized using attenuated total reflection-Fourier transformed infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and thermogravimetric analysis. The AESO/acr-RGO nanocomposite coatings were fabricated using UV-curing technology to covalently introduce graphene sheets into the AESO matrix. Real-time infrared and ATR-FTIR spectroscopy were used to monitor double-bond conversions and deep curing in the AESO/acr-RGO coating. Scanning electron microscope images revealed the homogeneous dispersion of acr-RGO in AESO. The thermal and mechanical properties of cured films were evaluated through thermogravimetric analysis, tensile testing, and dynamic mechanical analysis. The results revealed that the introduction of acr-RGO effectively enhanced the mechanical properties and the thermal stability of the host resin AESO. The optimal reinforcing effect was observed at 1.0 wt% acr-RGO loading, under which the tensile strength and storage modulus of the AESO/acr-RGO nanocomposite improved by 167% and 15%, respectively, compared with those of neat AESO. The initial degradation temperature of the AESO/acr-RGO nanocomposite was also sharply improved by 61 °C under a loading of 0.5 wt%. Additionally, a slight increase in the glass transition temperature of the AESO/acr-RGO nanocomposite from 29.6 to 36.1 °C was observed when acr-RGO was incorporated. Furthermore, introducing acr-RGO enhanced the coating properties. By contrast, the composite coating using amino-group functionalized graphene (AESO/ami-RGO) nanocomposites exhibited poorer mechanical properties and lower thermal stability than its acr-RGO counterpart. The remarkable property reinforcements are thus attributed to the acryloyl-group functionalization of graphene, which improved the compatibility and enhanced the interfacial adhesion of graphene with the AESO matrix.