Nonformaldehyde Crosslinking Agent Research Articles

Structural Analysis of Oxidized Sucrose and Its Application as a Crease-Resistant Crosslinking Agent.

Oxidized sucrose is a non-formaldehyde crosslinking agent with many applications in polymer crosslinking and modification, such as in the preparation of starch films and protein films. However, research on the structure of oxidized sucrose is lacking. In this paper, oxidized sucrose was synthesized through selective oxidation of sodium periodate. By LC-MS, FTIR, TGA, NMR, and HRMS analyses, it was shown that oxidized sucrose existed in the form of a hydrate, and the tetraaldehyde oxidized sucrose could isomerize into the form of two six-membered hemiacetal rings. The structure of oxidized sucrose was also verified by theoretical calculations. Furthermore, the diffusional properties of oxidized sucrose were investigated by the rolling-film method. Finally, it was found that oxidized sucrose used as a crosslinking agent could effectively improve the wrinkle recovery performance of cotton fabrics.

Improving antibacterial and sun protective properties of cotton fabrics via dual effect of nano-metal oxide and Moringaoleifera extract

Bleached cotton fabrics were pre-treated with moringa leaf extract as natural bioactive materials to impart the fabric dual antimicrobial and sun protective properties. The fabrics were the treated with TiO2NP and ZnONP separately with concentration 2%&1% respectivelyin presence of butane tetracarboxlyic acid as non-formaldehyde crosslinking agent by pad dry cure technique. The treated fabrics were evaluated via monitoring morphological changes of the fibers using scanning electron microscopy and electron diffraction X-ray (SEM&EDX), tensile strength, roughness, ultra violet factor (UPF) in addition to bioas-say of antimicrobial activity of the treated fabrics. Research output disclosed that the fabrics treated with moringa extract and then with titanium dioxide nanometal oxide powder show the best results.

Innovative ecological method for producing easy care characteristics and antibacterial activity onto viscose fabric using glutaraldehyde and chitosan nanoparticles

PurposeThis study aims to explore the incorporation of the authors previously prepared chitosan nanoparticles (CNPs) of size around 60-100 nm in the cross-linking formulation of viscose fabrics to see CNPs impact in terms of imparting multi-functional characteristics such as tensile strength, dry wrinkle recovery angles and antibacterial properties.Design/methodology/approachCNPs of size around 60-100 nm were incorporated in cross-linking formulations for viscose fabrics, including different concentrations of glutaraldehyde as a non-formaldehyde cross-linking agent and magnesium chloride hexahydrate as a catalyst. The formulations were applied at different curing times and temperatures in 100 mL distilled water, giving rise to a wet pickup of ca. 85 per cent. The fabrics were dried for 3 min at 85°C and cured at specified temperatures for fixed time intervals in thermo fixing oven according to the traditional pad-dry-cure method.FindingsThe above eco-friendly method for finished viscose fabrics was found to obtain high dry wrinkle recovery angle and maintain the tensile strength of the finished fabric within the acceptable range, as well as antibacterial properties against Escherichia coli and Staphylococcus aureus as a gram-negative and gram-positive bacteria, respectively. Both, scanning electron microscope and nitrogen percent on the finished fabric confirm the penetration of CNPs inside the fabric structure. Finally, viscose fabrics pageant antibacterial activity against gram-positive and gram-negative bacteria assessed even after 20 washing cycle.Research limitations/implicationsCNPs with its flourishing effect with respect to cationic nature, biodegradability, reactivity, higher surface area and antimicrobial activity; in addition to glutaraldehyde as non-formaldehyde finishing agent can be used as multi-functional agents for viscose fabrics instead of DMDHEU, polyacrylate and monomeric composites as hazardous materials.Practical implicationsCNPs as cationic biopolymers were expected to impart multi-functional properties to viscose fabrics especially with obtaining reasonable dry wrinkle recovery angle and tensile strength in addition to antibacterial properties.Originality/valueThe novelty addressed here is undertaken with a view to impart easy care characteristics and antibacterial activities onto viscose fabrics using CNPs as antimicrobial agent and glutaraldehyde as non-formaldehyde durable press finishes to-replace the traditional formaldehyde-based resins. Besides, to the authors’ knowledge, there is no published work so far using the above cross-linking formulation written above.

Optimization of reaction parameters and characterization of glyoxal-treated poplar sapwood

Glyoxal as a non-formaldehyde cross-linking agent was employed with ammonium persulfate as a novel catalyst to improve the dimensional stability and water resistance of poplar sapwood. The effects of various cross-linking parameters (e.g., glyoxal concentration, curing temperature, glycol-to-glyoxal molar ratio and catalyst concentration) on the properties of wood were investigated, and the parameters were optimized. In comparison with the unmodified wood, the glyoxal-modified wood exhibited improved dimensional stability and reduced water uptake. Moreover, the addition of glycol further strengthened the dimensional stability and anti-leaching ability. Modified wood was characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM) and contact angle instrument. IR indicated that the network structure was formed between the agent itself or cross-linking between wood components and glyoxal. SEM revealed the precipitation and filling effect of the cured glyoxal in the cell wall. Contact angle measurement further confirmed the improved hydrophobicity of wood after modification. All the results suggested that the improved dimensional stability and water resistance of the treated wood could attribute to both bulking effect and cross-linking reaction or network structure formed. However, it is not clear whether network structure by glyoxal itself or the cross-linking between the glyoxal and wood components is formed in wood.

Studies on Dimensional Stability of Indian Tassar Silk Fabrics by using Butane Tetra Carboxylic Acid (BTCA)

This article attempts to study the influence of 1,2,3,4-Butane tetra carboxylic acid (BTCA)treatment on the properties of tassar silk fabric. Indian tassar (Anthrea mylitta D) silk fabrics have been treated with BTCA, a non-formaldehyde cross-linking agent, in the presence of sodium hypophosphite monohydrate as the catalyst and non-ionic polyethylene emulsion as the softener. Fabric shrinkage (dimensional stability) in the warp and weft directions shows significant improvement after treatment and also, a 10% improvement in the fabric crease recovery is observed. Although the single yarn strength is not significantly affected, the elongation of yarn decreases by 15%. Similarly, the fabric tensile strength and air permeability properties are the least affected, but the fabric tearing strength significantly increases after treatment with BTCA. The treatment displays promising results for tassar fabrics, which are inherently susceptible to shrinkage issues.

Nonformaldehyde durable press finishing of cotton fabrics using the combination of maleic acid and sodium hypophosphite.

Polycarboxylic acids have been used as nonformaldehyde crosslinking agents for cotton with sodium hypophosphite (NaH2PO2) as the catalyst to replace the formaldehyde-based dimethyloldihydroxyethleneurea (DMDHEU). Maleic acid (MA), an α, β-unsaturated bifunctional carboxylic acid, can esterify cotton but is not able to form crosslinking between two cellulose molecules by itself. In this research, we discovered that the wrinkle resistance of the cotton fabric treated with MA and NaH2PO2 was significantly increased and phosphorus was bound to cotton when the treated fabric was exposed to temperatures higher than that required for esterification of cotton by MA. Elevation of the fabric wrinkle resistance and increase in quantity of the phosphorus bound to cotton had similar dependency on curing temperature, on MA concentration, and on NaH2PO2 concentration. All the data support the hypothesis that H-P-(residual of NaH2PO2) added to >CC< of the MA already bound to cotton by esterification, thus forming a new crosslink between two cotton cellulose molecules. The cotton fabrics treated by MA/NaH2PO2 showed fabric wrinkle resistance similar to that treated with DMDHEU, but the breaking strength and tearing strength of the MA-treated cotton fabrics were significantly improved.

Wrinkle-resistant finishing of cotton fabric with BTCA - the effect of co-catalyst

Fabrics treated with dimethyloldihydroxylethyleneurea (DMDHEU) are susceptible to formaldehyde release. High concentrations of formaldehyde have been reported to cause cancer in animal studies. Due to the toxicity of DMDHEU, the polycarboxylic acid class of non-formaldehyde crosslinking agents used for wrinkle-resistant treatment has been introduced. Among various researches, 1,2,3,4-butanetetracarboxylic acid (BTCA) is a desirable reactant when catalysed with sodium hypophosphite (SHP). The characteristics of TiO 2 or nano-TiO2, acting as a co-catalyst in a BTCA wrinkle-resistant finishing system are examined in this study. Surface morphology and molecular structure of cotton specimens together with the wrinkle-resistant, UV protection, yellowing, tensile and tearing properties of the treated specimens are also evaluated.

Effect of glycols and catalysts on cotton fabrics treated with glyoxal

The optimum conditions for durable press treatment of cotton fabrics using glyoxal as a nonformaldehyde crosslinking agent were investigated. Crosslinking reaction was conducted in the presence of different catalysts such as aluminum sulfate, magnesium chloride, or magnesium chloride-citric acid mixture at various mole ratios of catalyst to glyoxal. Aluminum sulfate was proven the most effective one among those used. Glycol addition into a glyoxal padding bath increased the wrinkle recovery angle(WRA) and whiteness of treated fabrics. The optimum mole ratio of glycol to glyoxal was 1:1. Diethylene glycol addition produced better overall performance to the glyoxal-crosslinked fabric compared to ethylene glycol addition.

Nonformaldehyde Durable Press Finishing of Cotton Fabric: Quantitative Evaluation of Cellulose-Bound Glyoxal

Cellulosic material is treated with formulations containing 14.5% (w/w) glyoxal (40%) as a nonformaldehyde crosslinking agent in order to impart durable press properties. MgCl 2 · 6 H2O and Al2(SO4)3 · 16 H2O are applied as catalysts and different hydroxy carboxylic acids (citric, tartaric, and malic acids) as co-catalysts. The amount of cotton- bound glyoxal is measured by means of isocratic HPLC using HPX-87H as a stationary phase. Prior to chromatographic analysis, the cotton-bound glyoxal is converted to glycolate by means of an internal Cannizzaro reaction. The results indicate that MgCl2 · 6 H2O possesses lower effectiveness in comparison to Al2(SO4)3 · 16 H2O. A reduction of the cure temperature from 150 to 110°C does not influence the portion of glyoxal that has reacted with the cellulose when citric, tartaric, or malic acids are added to the formulations as co-catalysts.

Applying a Nonformaldehyde Crosslinking Agent to Improve the Washing Durability of Fabric Water Repellency

1,2,3,4-Butanetetracarboxylic acid (BTCA) is confirmed to be an effective crosslinking agent with sodium hypophosphate (SHP) catalyst for washing durability improvement of cotton fabrics treated with fluorocarbon resin. By FTIR analysis, hydroxyl groups (—OH) are confirmed as a water repellency agent, so the resin can be theoretically crosslinked with the surface of the cotton fibers. The water repellency of the sample treated with fluorocarbon resin and 8% BTCA is much higher than the sample treated only with fluorocarbon resin. This kind of difference can be seen especially after fifty washing cycles and subsequent heat treatments, ESCA analysis confirms that the F/O ratio on the fabric surface changes dramatically after fifty washing cycles and subsequent heat treatment. The F/O of the sample treated with fluorocarbon resin and 8% BTCA is almost twice that of the fabric treated with fluorocarbon resin only. Crosslinks can restrict F loss and transfer into the inner part of the fibers. At the same time, this kind of treatment can effectively improve the crease resistance of cotton fabrics.

Determination of cotton-bound glyoxal via an internal cannizzaro reaction by means of high-performance liquid chromatography.

Glyoxal, a non-formaldehyde cross-linking agent, was applied in combination with aluminum sulfate hexadecahydrate to impart durable-press properties to cellulosic materials. The cotton fabric was impregnated with a pad bath formulation containing 6% (w/w) glyoxal and 4.5% (w/w) aluminum sulfate hexadecahydrate. The curing process was conducted at 140 degrees C for 3 min, thus affecting a cross-linkage between the cellulose chains. For the first time, a chromatographic method is presented that enables both qualitative and quantitative analysis of the portion of glyoxal that has reacted with the cellulosic material. For this purpose, the glyoxal-treated fabric was treated with an NaOH solution (c = 4 mol L(-1)) at 100 degrees C for 20 min. As a result, glyoxal was extracted from the cellulosic sample and converted into glycolate via an internal Cannizzaro reaction. Subsequently, the glycolate was analyzed chromatographically using the strong cation-exchange column Aminex HPX-87H as the stationary phase and sulfuric acid as the mobile phase. The detection limit was 1.87 mg L(-1) (UV detection). The recovery was 85%. Dry crease wrinkle recovery measurements gave evidence that the cross-linkage was removed completely. The application of the analytical technique developed in the present study demonstrated that the amount of glyoxal that had reacted with the cellulose was 15.7 +/- 0.72 mg/g of fabric. In addition, glycolate thus formed was well separated from non-formaldehyde durable-press finishing agents based on polycarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid or citric acid.

FTIR Spectroscopy Study of the Formation of Cyclic Anhydride Intermediates of Polycarboxylic Acids Catalyzed by Sodium Hypophosphite

In recent years, extensive efforts have been made to find formaldehyde-free durable press finishes to replace the traditional formaldehyde-based N-methylol compounds. 1,2,3,4-Butane-tetracarboxylic acid (BTCA) has been the most efficient nonformaldehyde crosslinking agent for cotton, with sodium hypophosphite (NaH2PO2) being the most effective catalyst. In our previous research, we found that a polycarboxylic acid esterifies cellulose through the formation of a five-membered cyclic anhydride intermediate by the dehydration of two adjacent carboxyl groups. In this research, we use Fourier transform infrared spectroscopy (FTIR) to study the formation of cyclic anhydride intermediates by BTCA and poly(maleic acid) (PMA) with and without the presence of NaH2PO2. In the absence of NaH2PO2, BTCA forms the cyclic anhydride only when the temperature reaches the vicinity of its melting point. In the presence of NaH2PO2, however, the anhydride forms at much lower temperatures. We have found that NaH2PO2 weakens the hydrogen bonding between the carboxylic acid groups of BTCA, contributing to accelerated anhy dride formation at lower temperatures. Sodium hypophosphite also accelerates the for mation of the anhydride intermediates by polycarboxylic acids in an amorphous state. The FTIR spectroscopy data show that there is a chemical reaction between the anhydride intermediate and NaH2PO2 when the temperature climbs above 200°C.

Formation of five-membered cyclic anhydride intermediates by polycarboxylic acids: Thermal analysis and Fourier transform infrared spectroscopy

Butanetetracarboxylic acid (BTCA) has been used as the most effective nonformaldehyde crosslinking agent for cotton and wood pulp cellulose. Our previous research has indicated that a polycarboxylic acid esterifies cellulose in two steps: the formation of a five-membered cyclic anhydride intermediate by the dehydration of two adjacent carboxyl groups, and the reaction between cellulose and the anhydride intermediate to form an ester linkage. In this research, we investigated the formation of carboxylic anhydrides by BTCA and other polycarboxylic acids in powder forms, and as finishes applied to cotton fabric using thermal gravimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopy. We found that BTCA and other polycarboxylic acids in powder forms start to form five-membered cyclic carboxylic anhydrides when the temperature reaches the vicinity of their melting points. The formation of carboxylic anhydride is accelerated above the melting points. We also found that BTCA forms anhydrides at lower temperatures when it is applied to cotton fabric as a finish. An increase in temperature increases both the amount of anhydride and the amount of ester formed on the cotton fabric. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2711–2718, 1998

Mechanical Strength of Durable Press Finished Cotton Fabrics

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.

FT-IR and FT-raman spectroscopy study of the cyclic anhydride intermediates for esterification of cellulose: I. Formation of anhydrides without a catalyst

In recent years, extensive efforts have been made to find nonformaldehyde durable press finishes to replace the traditional formaldehyde-based reagents for producing wrinkle-free cotton fabrics. 1,2,3,4-butanetetracarboxylic acid (BTCA) has been the most effective nonformaldehyde crosslinking agent. Our previous research has indicated that a polycarboxylic acid esterifies cellulose in two steps: the formation of a 5-membered cyclic anhydride intermediate by the dehydration of two adjacent carboxyl groups, and the reaction between cellulose and the anhydride intermediate to form an ester linkage. In this research, we used Fourier transform infrared and Fourier transform Raman spectroscopy to study the formation of cyclic anhydride intermediates by BTCA and other polycarboxylic acids without the presence of a catalyst. We found that BTCA and other polycarboxylic acids in a crystalline state start to form 5-membered cyclic carboxylic anhydrides when the temperature reaches the vicinity of their melting points with the exception of bifunctional acids, which form cyclic anhydrides at temperatures much higher than their melting points. Intermolecular hydrogen bonding between carboxylic acid groups prevents the formation of the cyclic anhydride intermediates at lower temperatures. We also found that polycarboxylic acids in an amorphous state form cyclic anhydrides at much lower temperatures.

Infrared spectroscopy studies of the cyclic anhydride as the intermediate for the ester crosslinking of cotton cellulose by polycarboxylic acids. III. Molecular weight of a crosslinking agent

Polycarboxylic acids have been used as nonformaldehyde crosslinking agents for cotton fabrics to replace the traditional N-methylol reagents. In this research, we compared 1,2,3,4-butanetetracarboxylic acid (BTCA) with poly(maleic acid) (PMA) as crosslinking agents for cotton cellulose. BTCA and PMA have similar molecular structures with carboxyl groups bonded to their molecular backbones, and both form five-membered cyclic anhydride intermediates during a curing process. However, BTCA is a more effective crosslinking agent for cotton cellulose than PMA. This is mainly attributed to the differences in the mobility of the anhydride intermediates to access the cellulosic hydroxyl groups during a curing process. The mobility of the anhydride intermediate of PMA is reduced due to its molecular size and multiple bonding between a PMA molecule and cellulose. Consequently, more anhydride and less ester are detected on the cotton fabric treated with PMA than on the fabric treated with BTCA. The amount of the unreacted anhydride intermediate on the fabric treated with PMA is reduced whereas the amount of ester is increased when another hydroxyl-containing compound of low molecular weight is present. Thus, the infrared spectroscopy data show a clear link between the molecular weight of a polycarboxylic acid and its effectiveness for crosslinking cotton cellulose. © 1997 John Wiley & Sons, Inc.

Formaldehyde-free zein fiber—preparation and investigation

A novel dry-spinning method for the preparation of zein fiber without using formaldehyde is presented. The fiber thus obtained had good stability to boiling aqueous acetic acid solution with breaking tenacity and elongation of 1.0 g/d and 30%, respectively. Citric acid and butanetetracarboxylic acid were used as nonformaldehyde crosslinking agents for the preparation of zein fiber successfully. Using polycarboxylic acids have advantages such as no toxicity and low sensitivity to the variation of processing conditions over formaldehyde containing stabilizers. The effects of crosslinking before and after stretching on improvement of fiber properties were discussed. Fiber morphological structure was also examined by means of wide angle x-ray diffraction and sonic velocity. © 1996 John Wiley & Sons, Inc.

Formaldehyde‐free zein fiber—preparation and investigation

A novel dry-spinning method for the preparation of zein fiber without using formaldehyde is presented. The fiber thus obtained had good stability to boiling aqueous acetic acid solution with breaking tenacity and elongation of 1.0 g/d and 30%, respectively. Citric acid and butanetetracarboxylic acid were used as nonformaldehyde crosslinking agents for the preparation of zein fiber successfully. Using polycarboxylic acids have advantages such as no toxicity and low sensitivity to the variation of processing conditions over formaldehyde containing stabilizers. The effects of crosslinking before and after stretching on improvement of fiber properties were discussed. Fiber morphological structure was also examined by means of wide angle x-ray diffraction and sonic velocity. © 1996 John Wiley & Sons, Inc.

Thermal properties of insolubilized polyacetals derived from non-formaldehyde crosslinking agents

Crosslinked polyols when applied to woven or non-woven fabrics impart high heats of fusion, lower thermal conductivity and several other physical properties. Previous publications have demonstrated that polyethylene glocols could be crosslinked onto a substrate with tetrafunctional cyclic urea compounds. A new formaldehyde free crosslinking system has been discovered using stoichiometric amounts of sulfonic acids and glyokal to form polyacetals with the same polyols. These polyacetals exhibit the same multifunctional properties and are also durable to laundering.

FT-IR Spectroscopy Study of the Ester Crosslinking Mechanism of Cotton Cellulose

Polycarboxylic acids are being developed as new nonformaldehyde crosslinking agents for cotton fabrics to replace the traditional N-methylol reagents. In this research, the mechanism of esterification between polycarboxylic acids and cotton cellulose was elucidated using FT-IR spectroscopy. All the infrared spectroscopic data support the hypothesis that cyclic anhydrides are formed as intermediates, which in turn esterify with cotton cellulose. The infrared spectroscopic data also demonstrate that cyclic anhydrides are very reactive and are able to esterify with cotton cellulose without a catalyst present and at a temperature much lower than the curing temperatures used for polycarboxylic acids. Therefore, the chief role of catalysts such as sodium hypo phosphite is that they accelerate the formation of a cyclic anhydride from a polycar boxylic acid.