No abstract

Replacing petroleum‐based raw materials with renewable materials is now obviously more in line with the needs of sustainable development. In this work, lignin, tung oil and linseed oil were selected to prepare tung oil modified lignin based phenolic resin (T‐LPF) and linseed oil modified lignin based phenolic resin (L‐LPF). T‐LPF and L‐LPF were characterized by FTIR, DSC, DMA, TGA, universal testing machine, SEM, friction and wear tester and 3D profilometer. The results show that compared with PF and LPF, the introduction of tung oil and linseed oil can reduce the curing activity and increase the curing peak temperature. The modified T‐LPF and L‐LPF have better thermal stability and mechanical properties. Compared with PF and LPF, the tensile strength of T‐LPF is increased by 33.4% and 41.75%, while the flexural strength is increased by 26.86% and 38.27% with the flexural strain increased by 68.97% and 91.41%. The tensile strength of L‐LPF is increased by 21.18% and 28.76%, while the bending strength is increased by 10.86% and 20.84% with the bending strain increased by 52.41% and 72.66%. T‐LPF and L‐LPF have better wear resistance than PF. They can be potentially used as resin matrix of high‐performance composites and friction composites.

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.

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-modi ed PF resins were synthesized using two avonoid 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 exural 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 exural 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 modi ed and enhanced by daidzein and naringenin have lower friction coe cient and more excellent wear resistance than pure PF.