Cross-linking of cellulose fibres. A model study using dimethylol ethylene urea (DMEU)

The process of fibre-fibre cross-linking during the textile process, curing, has been studied using a model fibre/cross-linking system, filter paper and dimethylol ethylene urea (DMEU). Interaction between the fibres and DMEU was investigated using differential scanning calorimetry (DSC), Diffuse reflectance Fourier-transform infrared (DRIFT) and Raman spectroscopies. DSC studies revealed that treatment with DMEU in the absence of catalyst resulted in a cross-linking reaction that produced a very diffuse endothennic curve with an onset at 80° and peaking at 165°. Also evident at higher (commercial flash) temperature were endotherms representing hydrolysis and decomposition of DMEU. The addition of a magnesium chloride catalyst to this system produced complex spectra but largely resulted in a shift of the curing-associated endotherm to a lower temperature. Analysis of the DRIFT spectra revealed that the cross-linking reaction did not require prolonged reaction times and that its was the superficial and amorphous cellulose regions that were associated with cross-linking. This was confirmed by cellulase digestion studies.