A Novel Bio-Mass Resveratrol-Modified Lignin-Based Phenolic Resin with High Glass Transition Temperature and Improved Mechanical Properties

In this study, resveratrol was substituted for phenol in different molar ratios (4%, 8%, 12%, 16% and 20%) with lignin, phenol and formaldehyde as raw materials, and a new resveratrol modified lignin-based phenolic resin (R-LPF) with high glass transition temperature (Tg) and improved mechanical properties was synthesized. The curing behaviors of phenolic resin (PF), lignin phenolic resin (LPF) and R-LPF were investigated. The thermal mechanical properties, thermal stability, comprehensive mechanical properties, frictional properties and morphology were systematically tested and analyzed. The results show that the highest Tg of the modified R-LPF reaches 346.2 °C. The Ts reaches 231.5 °C, and the residual carbon rate reaches 66.2% at 800 °C. For 12% substitution ratio, the maximum tensile strength, bending strength and impact strength are respective 28.72 ± 1.10 MPa, 57.58 ± 1.95 MPa and 3.14 ± 0.19 KJ/m2. Compared with PF and LPF, the tensile strength of R-LPF is increased by 21.5% and 40.4%, and the bending strength is increased by 6.5% and 30.4%, while the impact strength is increased by 38.9% and 58.6%, respectively. The wear resistance is also significantly improved. The modified R-LPF structure has good rigidity, high crosslinking density, excellent mechanical and thermal properties, and it makes up for the defects of system performance decline caused by the introduction of lignin and provides a direction for the development of green high-performance phenolic resin.