Preparation and Performance of Novel Flavonoid Phenols-Based Biomass-Modified Phenol Formaldehyde Resins

Low toxicity, environmentally friendly and sustainable bio-based phenol–formaldehyde (PF) resins are the primary factors and health goals that researchers need to consider when modifying PF resins. Two novel biomass-modified PF resins were synthesized using two flavonoid phenols of daidzein and naringenin with rigid backbone structures. The results show that compared with ordinary PF, the introduction of daidzein and naringenin during the synthesis of N-PF and D-PF can delay the curing reaction and results in higher curing peak temperatures. The appropriate substitution rate of daidzein and naringenin can improve the crosslinking degree, resulting in N-PF and D-PF with higher thermal stability, ablation resistance and mechanical properties. The highest carbon yield YC800 for N-PF is 59.81% (56.85%for PF-1), and the highest YC800 for D-PF is 64.39% (PF-2 with 58.15%). The maximum tensile strength and flexural strengths of N-PF are respective 33.86 MPa and 110.42 MPa (28.77 and 79.89 MPa for PF-1), and the maximum tensile strength and flexural strengths of D-PF are respective 35.61 MPa and 103.17 MPa (24.48 and 55.79 MPa for PF-2). The D-PF and N-PF resins modified and enhanced by daidzein and naringenin have lower friction coefficient and more excellent wear resistance than pure PF.