A new and relatively simple method for removing zinc nitrate-cured DMDHEU crosslinks from cotton cellulose is reported. The method entails boiling the finished fabric in 23% NaOH for 10 minutes. Removal of the finish was verified by nitrogen and formaldehyde analyses and by wrinkle recovery measurements. Little change

Cotton fabrics treated with various alkylated derivatives of DMDHEU were subjected to hydrolysis by urea-phosphoric acid, hot 23% sodium hydroxide, and urea-phosphoric acid followed by sodium hydroxide. Sequential treatment with acid and base removed more nitrogen and formaldehyde than the alkaline treatment, which removed more nitrogen and formaldehyde than the acid treatment. Stability of the crosslinks generated by these resins depended on both the degree of alkylation of DMDHEU and the nature of the alkyl cap. This stability was reflected in greater amounts of residual nitrogen and formaldehyde after hydrolysis. Those residues, in turn, affected the residual breaking strength, flex abrasion resistance, and wrinkle recovery of the hydrolyzed fabrics. The stability of the crosslinks also correlated well with formaldehyde release data for the treated fabrics.

The utility of alkaline hydrolysis as a method for removal of DMDHEU crosslinks from cotton is illustrated in this paper. The method was applied to fabric treated with DMDHEU/MgCl 2 and DMDHEU/MgCl2/citric acid mixed catalyst systems. Removal of the finish was complete as verified by nitrogen and formaldehyde analyses and by wrinkle recovery measurements. Losses in breaking strength and flex abrasion resistance produced in the cotton fabric upon treatment with DMDHEU were almost completely restored by the resin stripping. The DMDHEU/MgCl 2 treatment reduced the dpv (degree of polymerization by viscosity) of cotton by about 24% and DMDHEU/mixed catalyst treatment reduced it by about 18%. The quantity and chemical nature of the catalyst affect the ethyl acetate solubility of cellulose nitrate formed after stripping and nitration of crosslinked samples. Neither of the catalysts alone imparted ethyl acetate insolubility, but each catalyst by itself decreased the degree of polymerization of the cotton cellulose to a significantly greater extent than in the presence of DMDHEU. Fabrics treated with high concentrations of both catalyst systems could not be completely stripped of nitrogen and formaldehyde, and were not soluble in ethyl acetate (after nitration).

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