Synthesis of Lignin /Epoxy Resins in Aqueous Systems and Their Properties

A new resin system was developed only by mixing the alkaline solution of industrial kraft lignin with water-soluble epoxy compound, polyethylene glycol diglycidyl ether (PFGDGE), and curing reagent. The viscoelastic properties of cured resin films were investigated. As the content of the kraft lignin in the resins increased, the absorption peak due to the glass transition for cured resins shifted to a higher temperature with spreading. It was found that the glass transition temperature of cured resins can be modified by changing kinds of PEGDGE and curing reagents. Addition of the emulsion type of diglycidyl ether of bisphenol A (DGEBA) to the blendings also could make the glass transition temperature of cured resins higher. Since only one broad dispersion peak due to the glass transition could be observed, it was suggested that the cured resins had compatibility to form a kind of IPNs.