Abstract
The aim of this research is to develop a method for the synthesis of a lignin epoxy resin from lignin contained in plant biomass such as wood, rice straw, and bagasse. A physical and chemical pretreatment, i.e. steam explosion was used for the separation of lignin in the plant biomass. Wood chips of larch (Larix leptolepis) were treated under various explosional conditions such as steam pressure and steaming time. The exploded larch was separated into water soluble materials, a mixture of cellulose and low molecular substances, methanol soluble lignin, and Klason lignin. The characteristics of methanol soluble lignin were clarified by measuring IR spectra, molecular weight, methoxyl group, and phenolic hydroxyl group. The methanol soluble lignin extracted from the exploded larch at a steam pressure of 3.6MPa and a steaming time of 5min was the most adequate material for the synthesis of lignin epoxy resin. The methanol soluble lignin was converted into an excellent thermosetting resin by epoxidation and the epoxidized lignin was cured more quickly than commercial bisphenol A diglycidyl ether.
