Reaction of Aryl Isocyanates with Cotton Cellulose

Abstract

Nine cellulose N,N′-arylenedicarbamates have been formed by thermal reaction of the respective diphenyl arylenedicarbamates with cotton. Cotton print cloth was padded with a dimethylformamide (DMF) or dimethylsulfoxide (DMSO) solution of the diphenyl arylenedicarbamate and the reaction effected by in situ generation of the arylene diisocyanate in the curing step. Add-ons ranging from 3.8 to 12.0% were obtained; under comparable reaction conditions, more rapid reaction occurred with DMSO solvent rather than DMF. High degrees of cross-linking were indicated by high conditioned and high wet wrinkle recoveries. Decreases in breaking strengths, tearing strengths, and flex abrasion resistance were approximately of the same extent as normally encountered in other cross-linking treatments. Resistance to microbiological degradation for more than 89 days was shown by soil burial tests on the treated samples. Ease and extent of introduction and removal of creases by ironing were used to measure breaking and re-forming of carbamate cross links (reversibility). Ring methoxyl group activation of the N-phenyl carbamates appeared to be slightly more effective in achieving reversibility.