Reaction Mechanism of Dimethyloldihydroxyethyleneurea/ Alpha-amino Acids Co-reactants on the Crosslinking of Cotton Cellulose in the Presence of Aluminum Sulfate Catalyst

Abstract

Cotton fabrics were crosslinked with dimethyloldihydroxyethyleneurea (DMDHEU) alone and DMDHEU/alpha-amino acids. The results showed that the values of nitrogen content, dry crease recovery angle and wet crease recovery angle of the crosslinked fabrics were ranked as DMDHEU > DMDHEU/aspartic acid > DMDHEU/glycine > DMDHEU/arginine under the same concentration of crosslinking agent. The reaction rate constant was also in the rank of DMDHEU > DMDHEU/aspartic acid > DMDHEU/glycine > DMDHEU/arginine. This rank agreed with the number of amine groups on the alpha-amino acids. From the data of free energies of activation, we found that the alpha-amino acids could affect the crosslinking reaction. The transition state complex for DMDHEU alone was significantly different from those for DMDHEU/ alpha-amino acids. From infrared spectra, the interaction between alpha-amino acids and aluminum ion was confirmed. The mechanisms of the interaction between alpha-amino acids and aluminum ion and the condensation reaction mechanisms between DMDHEU and alpha-amino acids are suggested in this study. The higher the number of carboxylic acid groups contained in the alpha-amino acids, the higher the crease recovery angle and reaction rate constant.