PREPARATION AND REACTIONS OF EPOXY-ACTIVATED CELLULOSE

Abstract

Cellulose acetate fibers were treated with sodium methoxide in methanol for replacing acetyl group with sodium atom. The resulting sodium-contaning cellulose was treated with epichlorohydrine (ECH) in DMSO for preparing epoxy-activated cellulose (CGE). The amount of epoxy group introduced into cellulose increasing with sodium-content but was independent of the reaction time, reaction temperature or ECH concentration. Besides epoxidation, some side reactions occured through ring-opening reaction of epoxy group. CGE could be converted to various functional cellulosic materials through reactions with substances containing active hydrogen, such as amines, amino acids or carboxylic acids. Polyethylenimine (PEI) reacted easily with CGE in DMF. The PEI content of the product and the conversion of epoxy groups increased with decrease in molecular weight of PEI. Other amines such as ammonia, methylamine, dimethylamine or 4-aminopyridine also reacted with CGE. Since methylamine and dimethylamine reacted with CGE in similar ways, the reactivity was considered to be similar with primary and secondary amino groups in PEI. Glycine also reacted with CGE in aqueous solution, and the degree of the reaction increased with increase in pH of the solution. Glycine methyl ester hydrochloride dissolved in DMSO reacted easily with CGE by adding basic compound such as 1, 8-diazabicyclo [5, 4, 0] undecene-7 (DBU). Some carboxylic acids including propionic, n-butyric and succinic acids also reacted readily with CGE, especially in the presence of DBU. However, the reactivity of succinic acid was lower than that of glycine in an aqueous alkaline solution, suggesting that the amino group of glycine was more reactive than the carboxyl group to CGE in aqueous solution.