Elastomers based on cellulose fibers. II. Ethyl acrylate grafting onto disulfide‐crosslinked cellulose

Abstract

AbstractPartially disulfide‐crosslinked viscose rayon fibers (SS 2.3 mole/104 g. cellulose) were prepared by means of mercaptoethylation and successive oxidation and then grafted to the extent of 200–1200% graft‐on of ethyl acrylate with or without preswelling by zinc chloride, by using the ceric ion method. The tensile strength, breaking elongation, initial modulus, elastic recovery, and extension energy loss of the modified fibers were measured. In the disulfide‐crosslinked, about 1000% ethyl acrylate‐grafted fibers with preswelling, typical rubber elasticity was found. The disulfide crosslinkage in the grafted fibers was found generally to be capable of cleaving and re‐forming by the reduction and successive oxidation treatments, and the properties were also well reversible. Therefrom, it was confirmed that intermolecular crosslinking between cellulose molecules plays an important role for developing of elastomeric properties, as was found for the methylene‐crosslinked and grafted fiber reported previously. Most of elastomeric properties in our grafted fibers seem to be essentially attributable to the random conformation of the decrystallized, disoriented, and weakly crosslinked cellulose chains which are embedded in a matrix of flexible graft polymers.