Crosslinking of Cotton Cellulose in the Presence of Alpha-aminoacids Part III: Pore Structures

Abstract

The changes of the absorption bands of the infrared spectra for the cured dimethyloldihydroxyethyleneurea(DMDHEU)-aspartic acid in our previous study [1] revealed that the -OH group of DMDHEU could react with the amino and carboxylic acid groups of aspartic acid. In that study, we also found that the values of wet crease recovery angle (WCRA) and tensile strength retention (TSR) of the fabrics treated with DMDHEU-alpha-amino acids were higher, and dry recovery angles were lower than those expected from DMDHEU alone. The surface distribution of crosslinking agent on the fabrics treated with DMDHEU was similar to that with DMDHEU-alpha-amino acids. On the other hand, the rate constants for DMDHEU-alpha-amino acids were lower than those for DMDHEU alone, which was due to the significantly lower crosslinking reaction between alphaamino acids and cellulose than between DMDHEU and cellulose [2,3]. Those results strongly support the possibility that the crosslinking state and pore structure for DMDHEUaspartic acid might be different from that for DMDHEU. Many authors [4][5][6][7] have reported that the pore structures of the treated fabrics can be affected by varying the functional groups of crosslinking agents. However, detailed information about the pore structure for fabrics treated with DMDHEU-alpha-amino acids is lacking. 1 In the present study two direct dyes having molecular weight of 1356 and 767 g/mole, respectively, were used to study the pore structure of fabrics treated with DMDHEUAbstract Two kinds of alpha-amino acids were used to combine with dimethylol-dihydroxyethyleneurea (DMDHEU) as crosslinking agents. It was found that the values of equilibrium dye absorption, dyeing rate constant and the structural diffusion resistance constant for various combinations of crosslinking agents were in the rank of DMDHEU-glutamic acid > DMDHEU-aspartic acid > DMDHEU alone at the same dyeing temperature. The activation energies of dyeing for the three crosslinked fabrics were ranked as follows: DMDHEU > DMDHEU-aspartic acid > DMDHEU-glutamic acid. The patterns of fiber cross-section obtained by scanning electron microscopy showed that the degree of the swelling of the DMDHEU crosslinked fiber was somewhat lower than that of DMDHEU-alpha-amino acid crosslinked fibers. From this it was concluded that the fabrics crosslinked with the DMDHEUalpha-amino acid combinations had a larger pore structure.

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

“…IR spectra of the samples were obtained using a KBr disk technique [8]. Samples were prepared to give a dry weight of 1.8 mg after storage in 1-dram vials over P 2 O 5 for three days.…”

“…studies [3,7] pointed out that the carboxylic acid of tartaric acid could interact with aluminum ion to release hydrogen ions to improve the catalytic effect, the crease recovery angles and the reaction rate constants. Our previous studies [8,9] showed that the physical properties of the treated fabrics with DMDHEU/alpha-amino acids were changed with the kinds of alpha-amino acids used.…”