Cellulose-d,l-butadiene diepoxide reactions catalyzed by Lewis acids

Abstract

The reactions between cotton cellulose and the racemic mixture of d,l-isomers of butadiene diepoxide (BDO) in the presence of various Lewis acids have been studied. In particular, the zinc fluoborate-catalyzed reaction has been studied in various solvent media, with various mole ratios of reactants, and at various times and temperatures of cure. It has been shown that BDO will add to cotton from aqueous solutions to form products possessing dry and wet crease resistance provided the concentration of BDO is greater than 20%. Substitution of methanol for water results in excellent dry and wet crease resistant cottons after application of BDO at low concentrations followed by curing at relatively low temperatures (100–125°C.). In the wide epoxide/catalyst/AGU molar ratios investigated, weight gains were found to be relatively independent of concentrations used, but improvements in dry and wet crease angles depended on molar ratios of reactants. Application of BDO in methanolic solutions to cellulose of diverse accessibilities resulted in greatest improvement in crease recovery properties at lowest weight gain in ramie, the cellulose of highest crystallinity value. In addition, it was shown that BDO reacts with a number of chemically modified cottons. Dry crease resistance was improved in cottons acetylated to a low degree of substitution, dialdehyd cotton, and carboxymethylated cottons. Improvement in dry crease resistance was not observed in cottons acetylated to a high degree of substitution or in cyanoethylated cottons. The latter exhibited substantial improvement in wet crease resistance only. Possible reaction mechanisms have been considered.