Lignin polymerization of epoxy compound -2
Shirai shiN, also try after chemical modification of lignin synthesis – epoxy adhesive. In order to improve the reactivity of lignin, the alkali lignin phenol first with bisphenol A, phenol process, adding a small amount of hydrochloric acid or BF3 catalyst. Bisphenol A phenol-modified material in order to enhance the solubility of lignin, lignin obtained – Epoxy completely soluble in certain organic solvents include acetone, and measured using two different purified lignin (sugar content <4.5% and 11.7%) of the synthesized lignin two epoxy adhesive performance, less sugar found in 11.7% lignin bonding properties of synthetic resin which is better, there may be a saccharide units are involved in the reason. At 140 ℃ hot curing 5min, two kinds of epoxy resin has a satisfactory dry lignin, wet strength, while in the liquid added to the resin to improve the quality of CaCO3 - epoxy adhesive bond performance, because it The alkaline agent can be used as a curing accelerator, and serve to strengthen the effect as a filler. Outside, HCl, and BF3 as the lignin phenolic hydroxyl group introduced on an effective catalyst. Found using BF3-glycerol complex catalyst can be introduced only phenolic hydroxyl group, alcoholic hydroxyl group can be introduced. When there is an epoxy value of 0.48 BF3, and in the epoxy value 0.38 with HCl. BF3 catalyst using this synthetic resin, the use of triethyl diamine as a crosslinking agent, heat-pressed at 140 ℃ Maintenance, and tested using it as plywood adhesive performance, the results show that BF3 as a catalyst increases its water resistant adhesive strength.