Catalytic Effects and Selective Hydrolysis of Dimethylol Ethyleneurea and Formaldehyde Crosslinks in Finished Cotton

Abstract

Chemical analyses, physical testing, and selective hydrolysis of the finished fabrics were used to determine differences in chemical structure that resulted from treatment of cotton with dimethylol ethyleneurea (DMEU), formaldehyde, and a mixture of the two with strong or moderate catalysts. The strong catalyst was hydroxymethanesulfonic acid, which was produced by reaction of sulfurous acid and free formaldehyde present in the pad bath. Magnesium chloride was the moderate catalyst used. From combinations of the data the number of crosslinks in the treated cottons was calculated. Stability to acidic hydrolysis indicated the nature of the structures present in the crosslinks. Electron micrographs from application of cupriethylenediamine hydroxide (cuene) solubility and layer expansion techniques provided additional evidence to support these findings. Results are in general agreement with present theories of crosslinking to give wrinkle resistance in cellulosic materials. In addition they furnish new information on the treatment of cotton with a combination of agents that exhibit different reactivities and different stabilities of the crosslinks introduced.