Gary C. Lickfield

Mechanical Strength of Durable Press Finished Cotton Fabrics Part I: Effects of Acid Degradation and Crosslinking of Cellulose by Polycarboxylic Acids

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.

Mechanical Strength of Durable Press Finished Cotton Fabric Part II: Comparison of Crosslinking Agents with Different Molecular Structures and Reactivity

In our previous research, we investigated the strength loss of durable press cotton fabric caused by acid-catalyzed depolymenzation. In this paper, we study the relationship between the tensile strength loss of crosslinked cotton fabric and the molecular structures of the crosslinking agents. We use 1,2,3,4-butanetetracarboxylic acid (BTCA) and all-cis-1,2,3,4- petanetetracarboxylic acid (CPTA), linear and cyclic terrafunctional carboxylic acids, respec tively, to treat cotton at different concentrations and different temperatures. We find that BTCA is more effective and imparts higher levels of wrinkle resistance than CPTA, but the relationship between tensile strength loss and wrinkle recovery angle (WRA) for the treated fabric is independent of the differences in their molecular structures and reactivity. We also compare the tensile strength loss of cotton fabric treated with DMDHEU and 1,3-dimethyl-4,5-dihydroxyl ethyleneurea (DHDMI) and observe a similar phenomenon.

Mechanical Strength of Durable Press Finished Cotton Fabric. Part IV: Abrasion Resistance

Durable press (DP) finishing, a process widely used by the textile industry to produce wrinkle-resistant cotton fabrics, causes considerable loss of fabric abrasion resistance. N-methylol compounds such as dimethyloldihydroxylethyleneurea (DMDHEU) are traditional durable press finishing agents. In recent years, multifunctional carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid (BTCA) have been used as nonformaldehyde alternatives. In this research, we investigate the loss in fabric abrasion resistance caused by degradation and crosslinking of cellulose. Treatment of cotton by a polycarboxylic acid or a catalyst for DMDHEU results in a significant loss of its abrasion resistance. The lost abrasion resistance of cotton treated with BTCA is attributed to irreversible acid-catalyzed depolymerization and reversible crosslinking of cellulose molecules. We have removed the crosslinking of BTCA-treated cotton fabric with alkaline hydrolysis, thus determining separately the magnitude of lost fabric abrasion resistance due to the two different factors. For a warp-faced twill weave cotton, the reduced abrasion resistance in the warp direction is more severe than in the filling direction.

Chemical analysis of 1,2,3,4-butanetetracarboxylic acid

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.

Cellulase Treatment of Durable Press Finished Cotton Fabric: Effects on Fabric Strength, Abrasion Resistance, and Handle:

Enzyme washing is commonly used as a wet process technique to improve textile handle, appearance, and other surface characteristics of cottons in the industry. In this research, we have studied the effects of cellulase treatment on tensile strength, flex abrasion resistance, and handle of cotton fabric crosslinked by a polycarboxylic acid. The fabric is first treated with cellulase (pre-curing treatment), then crosslinked by 1,2,3,4- butanetetracarboxylic acid (BTCA). The fabric is also crosslinked by BTCA first then treated with cellulase (post-curing treatment). We compare the performance of the durable press (DP) finished cottons treated with cellulase using these two different procedures, and we find that the pre-curing cellulase treatment has a more positive influence on fabric handle than the post-curing treatment, but it also causes significantly higher fabric strength loss than the post-curing treatment. We also find that the difference in wrinkle resistance of the DP finished cotton fabrics with the two treatments is not significant. Considering the fact that a DP finishing process reduces fabric strength, the pre-curing cellulase treatment method should be used only for heavy cotton fabrics with high original strength.

Crystallization Kinetics Study of Polyethylene

Abstract Crystallization kinetics of polyethylene was studied using differential scanning calorimetry. Isothermal crystallization kinetics was analyzed using the Avrami equation. Non-isothermal crystallization kinetics was analyzed using different models, namely, the Avrami, Jeziorny, Ozawa, Nakamura, Dietz, and Kamal-Chu models. The advantages and disadvantages of these models are outlined based on comparison between experimental and modeling results.

The reaction of amines with N,N′-ethylenebis(salicylideneiminato)(nitrato)-iron(III) and related complexes

Abstract The title compound, Fe(salen)NO 3 , was reacted with imidazole, 1-methylimidazole, piperidine, and morpholine in either chloroform or dichloromethane solution. The reactions were monitored with proton NMR and electronic spectra and conductance measurements. The imidazole bases appeared to react with the complex in a 2:1 fashion with displacement of the nitrate, producing a high-spin iron(III) complex. The secondary amines promoted hydrolysis with any trace water present to form [Fe(salen)] 2 O. The chloro complex, Fe(salen)Cl, did not react with the imidazole bases, but did form the μ-oxo complex when a large excess of piperidine was present. The N,N′-phenylenebis-(salicylideneimine) complex, Fe-(salphen)NO 3 , was found to precipitate from an imidazole (im) chloroform solution as the high-spin complex, Fe(salphen)NO 3 ·2im.