A New and Effective Method for Removing DMDHEU Crosslinks from Cotton 1

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 in viscometric degree of polymerization (dpv), copper number, carboxyl content, breaking strength, and abrasion resistance of an untreated control fabric subjected to alkaline hydrolysis indicated that the stripping method was nondegradative. Losses in breaking strength and flex abrasion resistance produced in the cotton fabric upon treatment with DMDHEU were almost completely restored by resin stripping. Relatively small increases in reducing groups and carboxyl content and a dp loss of only about 13% (500 out of 3700) indicated that treatment of cotton with the DMDHEU/zinc nitrate system produced little chemical damage in the cellulose.