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Polycarboxylic acids have been the most promising durable press finishing agents for cotton to replace traditional formaldehyde-based reagents. Among the various polycarboxylic acids investigated in recent years, 1,2,3,4-butanetetracarboxylic acid (BTCA) has been the most effective crosslinking agent. Cottons treated with BTCA have shown superior durable press performance with high levels of laundering durability. In this research, we analyze a reagent grade and an industrial grade BTCA using elemental analysis and acid-base titration. The titration data indicate that the industrial grade product contains approximately 95% BTCA. The two BTCA products are studied by FTIR and FT-Raman spectroscopy, proton magnetic resonance spectroscopy (1H-NMR), mass spectroscopy (MS), and liquid chromatography/mass spectros copy (LC/MS). All the instrumental analysis data indicate the low level of impurities in the industrial BTCA. Cotton fabrics treated with the two products show similar durable press performance, indicating that the differences in effectiveness for crosslinking cotton between these two BTCA products are insignificant. The data also show that the impurity in the industrial grade BTCA does not cause fabric yellowing. [ABSTRACT FROM PUBLISHER]

In recent years, extensive efforts have been made to find nonformaldehyde durable press finishes to replace the traditional formaldehyde-based reagents. In this research, glutaraldehyde is evaluated as a nonformaldehyde durable press finish for cotton fabrics. The infrared spectroscopy data show that the two aldehyde groups of glutaraldehyde react with cotton at elevated temperatures. There is a linear correlation between the fabric wrinkle recovery angle and the reduction in the carbonyl band intensity of the treated cotton cured at increasing temperatures. We have compared glutaraldehyde with low- formaldehyde DMDHEU and nonformaldehyde DHDMI as crosslinking agents for cotton. The fabric finished with glutaraldehyde shows adequate wrinkle resistance, sufficient white ness, and high strength retention. As a nonformaldehyde durable press finishing agent, the performance of glutaraldehyde is superior to that of DHDMI. [ABSTRACT FROM PUBLISHER]

Citric acid (CA), one of the polycarboxylic acids used as crosslinking agents for cotton, is cost-effective and environmentally friendly, but its tendency to discolor fabric is a major disadvantage for white fabrics. In this research, we investigate cotton fabric yellowing caused by citric acid at elevated temperatures. We find that yellowing increases as curing temperature, curing time, and CA concentration increase. Using sodium hypophosphite as a catalyst causes less fabric yellowing than monosodium phosphate. The wet analysis data demonstrate that an alkene double bond is formed on cotton fabric treated with CA under curing conditions. Nuclear magnetic resonance (NMR) data indicate that CA is partially converted to trans- and cis-aconitic acids on cotton through dehydration. The visible spectra of fabric treated with trans- and cis-aconitic acids and cured at elevated temper atures show strong absorption in the 400-550 nm region. For polymeric multifunctional carboxylic acids, an increased number of hydroxyl groups in their molecules increases fabric yellowing. Therefore, yellowing caused by citric acid and other hydroxyl multi functional carboxylic acids can probably be attributed to the formation of unsaturated polycarboxylic acids. [ABSTRACT FROM PUBLISHER]

Severe tensile strength loss is the major disadvantage of durable press finished cotton fabrics. Such strength losses have been attributed to two main factors: acid-catalyzed depolymerization and crosslinking of cellulose molecules. In this research, we inves tigate the effects of acid degradation and cellulose crosslinking on the tensile strength of cotton fabric crosslinked by polycarboxylic acids. Multifunctional carboxylic acids such as butanetetracarboxylic acid (BTCA) are used as nonformaldehyde crosslinking agents for cotton fabrics. The strength loss caused by acid degradation is an irreversible process, and the magnitude of the loss is determined by the curing temperature and time, the dissociation constants of the acid, and the concentration and pH of the acid solution applied to the fabric. Crosslinking of cellulose molecules by a polycarboxylic acid causes a reversible fabric strength loss, which increases as the degree of crosslink ing increases. The magnitude of tensile strength loss caused by acid degradation and that by crosslinking for cotton fabrics treated with BTCA is measured. Losses caused by crosslinking can be restored after the ester crosslinking is hydrolyzed under alkaline conditions. [ABSTRACT FROM PUBLISHER]

Multifunctional polycarboxylic acids have been used as nonformaldehyde cross linking agents for cotton fabrics to replace the traditional N-methylol reagents. Ester ification of cotton cellulose by seventeen aliphatic and aromatic polycarboxylic acids is studied using Fourier transform infrared spectroscopy. Five-membered cyclic an hydride intermediates formed under the curing conditions are identified on cotton fabrics treated with these acids. Only those polycarboxylic acids that form cyclic an hydride intermediates esterify cotton cellulose. Formation of the cyclic anhydride intermediates and esterification of cotton cellulose take place in the same curing tem perature regions. The infrared spectroscopy data also indicate that the second carboxyl group in a bifunctional carboxylic acid is not able to esterify cotton cellulose effectively. Therefore, we can conclude that a polycarboxylic acid esterifies cotton cellulose through the formation of a cyclic anhydride intermediate. The infrared spectroscopy data also reveal that 1,2,3,4-butanetetracarboxylic acid is the most effective crosslinking agent for cotton cellulose among the acids studied. [ABSTRACT FROM PUBLISHER]

Cotton fabrics were treated with dimethyloldihydroxyethyleneurea (DMDHEU) and methylated DMDHEU using conventional padding and a foam finishing tech nique. The finished fabrics were studied using Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS). Both finishing agents appeared to have a more homo geneous distribution in the foam finished fabrics than in the conventionally finished fabrics. This probably explains the observation that wrinkle recovery angle was generally higher for foam finished fabrics than for conventionally finished fabrics, since a more homogeneous distribution of the finishing agents allows more cotton cellulose to be crosslinked throughout the fabrics. [ABSTRACT FROM PUBLISHER]