Study On Activation Of Lignin And Modifying Epoxy Resin

Lignin is three-dimensional network macromolecule whose content is lower than cellulose in botanic field and containing variouses functional groups, developing valid utilization of lignin has profound social and economic meaning.This study adopts wheat straw alcohol solution lignin with ionic liquid as reaction medium, modified with AA and CP and preparing EP composite material.It is studyed that the chemical structures, thermal properties and micromorphology of wheat straw alcohol solution lignin by FTIR spectrum, test of hydroxyl value, TGA and SEM. There are amounts of hydroxy in the structure of lignin, it has the fastest decomposition rate in the range of241℃-426℃.Lignin Scattered unevenly and the agglomeration is caused easily.Odropting [C4mim]Cl ionic liquid as reaction medium, and without of any reaction promoter and catalyst, modifying lignin with AA and CP. By the study of the modifying tempreture, modifying time and molar ratio of the modifying reagent and lignin, examining their influence on percent grafting,and the modifying condition is optimized. Researches show that:with increase of mole ratio of substrate, the percent grafting of modified lignin is improved.The best modifying condition is:acetylated tempreture90℃, acetylated time2h; esterified tempreture80℃, esterified time3h.The analysis of FTIR shows that both of the AA and CP react with hydroxy of lignin.Test of TGA shows that heat stability of modified lignin is increased obviously. The analysis of SEM shows that particle size of acetylated lignin is decreased and it is more homogeneous compared with lignin; particle size of esterified lignin is increased and appearing circular aperture of all size.EP/lignin composite material is prepared with base of EP, and wheat straw alcohol solution lignin, acetylated lignin and esterified lignin of the best condition as modified additive, discussing the influence of different content on the performance of the composite material. Heat stability of composite material is increased by the addition of acetylated lignin and esterified lignin, and the20%content composite material with the best heat stability; Vicat heat deflection and bending strength has increased, and the raise of the adhesive tensile enhancing the bonding properties of EP.