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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. [ABSTRACT FROM AUTHOR]

It is of interest to develop wide-temperature domain damped hydrophobic materials. In this paper, we designed incorporating bio-based phenolic resin into the IIR matrix and introducing dibenzyl fork acetone (DBA) into the main chain structure with sodium hydroxide activation to construct three-dimensional network. In this paper, we designed incorporating bio-based phenolic resin into the IIR matrix and introducing dibenzyl fork acetone (DBA) into the main chain structure with sodium hydroxide activation to construct three-dimensional network. The added bio-based phenolic resin has reticulated structure blended with butyl rubber, combined with sodium hydride activation-modified IIR. The results show that sodium hydride activated modification of DBA is introduced into the main chain structure of IIR by infrared and 1H NMR analysis. The material hydrophobic is realized by the introduction of DBA with static water contact angle of 103.5°. The addition of 10phr lignin-based phenolic resin (LPF) is compatible with IIR, and the torque can reach 7.0 N-m. The tensile elongation of the modified butyl rubber composite can reach 2400% with tensile strength up to 11.43 MPa, while the damping factor can reach 0.37 even at 70 °C. The thermal stability of the composites is enhanced with mass retention rate of 28%. The bio-based PF/NaH activation-modified butyl rubber damping material has potential applications in damping hydrophobicity with wide temperature range. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Walnut shell pyrolysis liquefaction experiments for phenolic enrichment were conducted using torrefaction pretreatment and fractional condensation simultaneously. Bio-oil composition was comprehensively analyzed for elements, functional groups and componential contents. After high-temperature torrefaction, the proportion of lignin pyrolytic products in pyrolysis organic vapors showed significant increment. Fractional condensation further separated water, acetic acid and other small molecular compounds, and improved the phenolic content in the target bio-oil. Compared with the traditional pyrolysis liquefaction technology, when 363 K water bath was utilized to recover 300 °C torrefied walnut shell pyrolysis vapors, the C/O ratio in bio-oil increased from 0.5 to 1.6, and the proportions of H in aromatic ring and phenolic OH increased by 150% and 400%, respectively. The total content of detectable phenols was enriched from 2.7 wt% to 13.3 wt%. The optimized scheme on improving economic efficiency was provided for offsetting torrefaction energy consumption and low bio-oil yield. • Torrefaction pretreatment and fractional condensation were used to prepare bio-oil. • Variation in bio-oil composition under different preparation conditions was analyzed. • Phenolic enrichment mechanism by torrefaction and condensation was clarified. • Optimal temperatures of torrefaction and condensation were given to maximize phenols. • A revised scheme was provided for offsetting the disadvantages of torrefaction. [ABSTRACT FROM AUTHOR]

The potential for electrochemical conversion of bio-oil was overlooked for a long period due to the poor electrical conductivity and unclear reaction mechanism. This study aimed to provide an insight into bio-oil of electrochemical conversion mechanism and product distribution. In this study, using walnut shell bio-oil with enhanced electrical conductivity by ammonium carbonate as raw material, electrolysis experiments were carried out using different electrolysis times by constant current method (20 mA) in H-type electrolytic cell at a stable temperature (0 °C). The results showed that phenols, aldehydes, and lignin were copolymerized; meanwhile, unsaturated fatty acids such as oleic acid underwent decarbonylation and decarboxylation. The hydrogen-releasing electrode reaction also occurred at the cathode during the conversion process. Besides, the properties of products were characterized by elemental analysis, GC-TCD/FID, GC/MS, 1H NMR, FTIR, and TG-FTIR. Solid products were of possibility for application in new materials owing to containing copolymers with lignin structure, and gas products could be utilized as gas fuels with the combustible gas (H2, CO, CH4, and olefins) content as 79.24%. [ABSTRACT FROM AUTHOR]