Valorization of Technical Lignin for the Production of Desirable Resins with High Substitution Rate and Controllable Viscosity

Abstract

The valorization of lignin to replace phenol is significant in the production of phenolic resins. However, a great challenge is to produce lignin‐based resin (LR) with a suitable viscosity and high substitution rate of lignin to phenol. In this study, LRs were produced using hardwood technical lignin derived from the pulping industry. Structural analysis of the LRs indicated that the unsubstituted para and ortho carbon atoms of the aromatic ring influenced the curing temperature and activation energy of the resins. The curing kinetics and thermal decomposition study implied that urea and methylene groups in cured LRs were significant factors that affected the thermal stability negatively. The prepared LRs showed desirable features if used as adhesives to make plywood. This is the first approach in which a substitution rate of up to 65 % is achieved for low‐reactive‐site hardwood lignin, which provides a solution to the challenge of the simultaneous realization of the high addition of lignin and the adaptive viscosity of resins.

Improved value and carbon footprint by complete utilization of corncob lignocellulose

“…As shown in Fig. 3, the intensities of the unsubstituted carbons of L 2 PF resin adhesive are markedly lower than another one, which resulted in a lower curing temperature of L 2 PF resin adhesive [58].…”

“…Traditionally, the lignin used to prepare resins is usually purified first to decrease the adverse effects from carbohydrates and other impurities on the adhesive properties. Previously, we have reported the valorization of technical lignin [57,58] as well as bioethanol fermentation residues [59] for the production of desirable resins with high substitution rate and controllable viscosity. Further application of LPF resin adhesives in large scale via our developed technology for the production of plywood in China demonstrated an innovative costs reduction strategy for related industrial processes [60].…”

Preparation of Graphene-Like Porous Carbons With Enhanced Thermal Conductivities From Lignin Nano-particles by Combining Hydrothermal Carbonization and Pyrolysis

“…Of the various precursors used to prepare porous carbons, lignin is attractive because of its high carbon content (∼55-65%) and abundant supply from the pulp and paper industries. Lignin is a byproduct of wood pulp delignification (Pang et al, 2020b;Yoo et al, 2020). Dissolved lignin (typically in a solution called black liquor) is commonly burned to recover pulping chemicals and provide steam for power production (Shuai et al, 2016;Pang et al, 2020a).…”

“…Lignin is a byproduct of wood pulp delignification (Pang et al, 2020b;Yoo et al, 2020). Dissolved lignin (typically in a solution called black liquor) is commonly burned to recover pulping chemicals and provide steam for power production (Shuai et al, 2016;Pang et al, 2020a). However, some manufacturers have begun to develop lignin products of lignosulphonate, adhesive, and foam as additional revenue streams for pulp and paper mills (Li and Ragauskas, 2012;Pang et al, 2020b;Pei et al, 2020).…”

“…Dissolved lignin (typically in a solution called black liquor) is commonly burned to recover pulping chemicals and provide steam for power production (Shuai et al, 2016;Pang et al, 2020a). However, some manufacturers have begun to develop lignin products of lignosulphonate, adhesive, and foam as additional revenue streams for pulp and paper mills (Li and Ragauskas, 2012;Pang et al, 2020b;Pei et al, 2020). Lignin is also chemically well-suited to transformation into graphenelike porous carbons, particularly because they contain functional groups and have an abundance of benzene rings (Liu et al, 2017;Dong et al, 2020;Wang et al, 2020).…”