Reagent Residues of DMEU on Cotton Fabric as a Function of Pad-Bath pH and Storage Period of the Treated Fabric

The effect of pad-bath pH and storage of padded fabric on the stability of DMEU was investigated. In addition to the expected demethylolation products, MMEU and EU, other oligomeric/polymeric materials were generated. Since the latter were not quantifiable by liquid chromatography, they were measured by nitrogen analysis. Some of the oligomeric residues were water soluble and were extracted along with the DMEU, MMEU, and EU, while others were water insoluble and remained on the fabric. When padded from a bath of pH 6-10, DMEU was stable on the fabric for about two days. As pH was decreased from 6 to 3, formation of water-soluble oligomers and water-insoluble polymers increased significantly. At pH 10, even after 15 days, no oligomer/polymer was observed as the total residue was accounted for by the DMEU, MMEU, and EU. Differences between DMEU and DMDHEU under similar pH and storage conditions are discussed.