Modification of cotton with acrylonitrile by radiation polymerization

Abstract

The modification of cellulose (cotton fabric or yarn) has been carried out with acrylonitrile under ionizing radiation. Irradiation of the cotton in aqueous acrylonitrile solutions with gamma‐ or electron radiation produces a modified cotton with improved rot and mildew resistance similar to that of cyanoethylated cotton. Strength properties are not significantly affected, provided the radiation dose is less than 5 Mrads. The pickup of acrylonitrile by cotton depends on monomer concentration, dose, and dose rate. It was also observed that water was necessary to give the desired uniform modification. Doses of 0.5–1.5 Mrads produced modifications in the range of 8–15%. Dose rate effects are present at low doses, where pickup decreases with increasing dose rate. Above 5 Mrads, dose rate effects are minimized. Although the data do not show whether actual grafting is occurring with the cellulose, either directly from radiation or through oxidative products formed in the water, or whether the cellulose is being swollen with the aqueous monomer solution which is then intimately polymerized by radiation fragments resulting from the radiation, it is apparent that polymer is formed uniformly upon or within the cellulose structure and that it cannot be removed by solvent extraction. As a result of the modification, the solubility of the cellulose in its usual solvents is decreased and other properties are modified, especially rot resistance, which is improved. Modification of cotton with monomers other than acrylonitrile has also been considered. Pickups of styrene, acrylic acid, methyl isopropenyl ketone, ethyl acrylate, and methyl methacrylate have been obtained from methanol–water solutions.

The role of additives in the radiation induced copolymerization of monomers to cellulose

“…Relatively little use has been made of many of these solvents with the exception of the lower alcohols. Thus dioxan has been employed only in grafting with cellulose acetate [6] , attempts to copolymerize acrylonitrile to cotton with the solvent being unsuccessful [7]. Dimethylformamide (DMF) has been used with cellulose acetate [8] and some studies of acetone and n-butylamine with cellulose have also been performed [9] .…”

“…The importance of water on the grafting process has been discussed by many authors; the presence of water in the grafting solution usually increasing the copolymerization [7,4149]. The optimum amount of water has still not been clarified for all radiation conditions, however work already performed indicates that a number of factors are involved including the type of cellulose.…”

Electrochemical grafting of methyl methacrylate onto cellulose

“…These include ozonization ( l ) , U.V. radiation (2), and ionizing radiation (3)(4)(5)(6). In most cases, weight increase of the cellulose after vigorous extraction of the vinyl polymer (and monomer) has been taken a s indication of a true graft.…”