Wrinkle Recovery Angle Research Articles

Formaldehyde free cross-linking agents based on maleic anhydride copolymers

Low molecular weight copolymers of maleic anhydride and vinyl acetate were prepared to develop formaldehyde free cross-linking agents. Since lower molecular weight is favorable for efficient penetration of the finishing agent into the cotton fibers in the padding process, the concentration of the initiator, chain transfer agent and the monomer ratios were varied to obtain copolymers of low molecular weights. The prepared polymers were characterized by GPC,1H-NMR, FTIR, DSC and TGA. Copolymers of molecular weights of 2 000 to 10 000 were obtained and it was found that the most efficient method of controlling the molecular weight was by varying the monomer ratios. Poly(maleic anhydride-co-vinyl acetate) did not dissolve in water, but the maleic anhydride residue hydrolyzed within a few minutes to form poly(maleic acid-co-vinyl acetate) and dissolved in water. However, the maleic acid units undergo dehydration to form anhydride groups on heating above 160 °C to some extent even in the absence of catalysts. The possibility of using the copolymers as durable press finishing agent for cotton fabric was investigated. Lower molecular weight poly(maleic anhydride-co-vinyl acetate) copolymers were more efficient in introducing crease resistance, which appears to be due to the more efficient penetration of the crosslinking agent into cotton fabrics. The wrinkle recovery angles of cotton fabrics treated with poly(maleic anhydride-co-vinyl acetate) copolymers were slightly lower than those treated with DMDHEU and were higher when higher curing temperatures or higher concentrations of copolymer were used, and when catalyst, NaH2PO2, was added. The strength retention of the poly(maleic anhydride-co-vinyl acetate) treated cotton fabrics was excellent.

Acrylic and Maleic Acids in Nonformaldehyde Durable Press Finishing of Cotton Fabric

This study examines the possibility of using unsaturated acrylic and maleic acids to impart durable press performance to cotton fabric. The two acids are copolymerized with potassium persulfate as the initiator and sodium hypophosphite monohydrate as the catalyst. The copolymer is used to finish cotton fabric by the padding and curing method. FTIR spectra confirm that crosslinking between the carboxyl groups of acids and the hydroxyl groups of cellulose occurs by means of the esterification reaction. The effects of curing conditions and reagent concentrations on the dry wrinkle recovery angle, tensile strength, and whiteness of finished fabrics are thoroughly investigated. The results indicate that at certain conditions and concentrations, durable press finishing of cotton fabric with the copolymer provides good wrinkle resistance comparable to fabric treated with DMDHEU. However, the copolymer treatment does not provide as good tensile strength and whiteness as DMDHEU.

Durable antimicrobial treatment of cotton fabrics using N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride and polycarboxylic acids

AbstractN‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride (HTCC), a water‐soluble chitosan quaternary ammonium derivative, was used as an antimicrobial agent for cotton fabrics. HTCC has a lower minimum inhibition concentration (MIC) against Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli compared to that of chitosan; however, the imparted antimicrobial activity is lost on laundering. Thus crosslinking agents were utilized to obtain a durable antimicrobial treatment by immobilizing HTCC. Several crosslinkers such as dimethyloldihydroxyethylene urea (DMDHEU), butanetetracarboxylic acid (BTCA), and citric acid (CA) were used with HTCC to improve the laundering durability of HTCC treatment by covalent bond formation between the crosslinker, HTCC and cellulose. The polycarboxylic acid treatment was superior to the DMDHEU treatment in terms of prolonged antimicrobial activity of the treated cotton after successive laundering. Also, the cotton treated with HTCC and BTCA showed improved durable press properties without excessive deterioration in mechanical strength or whiteness when compared to the citric acid treatment. With the addition of only 0.1% HTCC to BTCA solutions, the treated fabrics showed durable antimicrobial activity up to 20 laundering cycles. The wrinkle recovery angle and strength retention of the treated fabrics were not adversely affected with the addition of HTCC. Therefore, BTCA can be used with HTCC in one bath to impart durability of antimicrobial activity along with durable press properties to cotton fabric. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1567–1572, 2003

Crosslinking cotton with poly(itaconic acid) and in situ polymerization of itaconic acid: Fabric mechanical strength retention

AbstractPolycarboxylic acids have been used as nonformaldehyde durable press finishing agents for cotton fabrics. Previously, we found that itaconic acid (IA) polymerized in situ on cotton fabric and also in an aqueous solution in the presence of a K2S2O8/NaH2PO2 initiation system. Both poly(itaconic acid) (PIA) and the polymer formed by in situ polymerization of IA are able to crosslink cotton cellulose, thus imparting wrinkle resistance to cotton. In this research, we compared the performance of the cotton fabric crosslinked by PIA and that crosslinked by in situ polymerization of IA. The fabric treated with PIA and that treated with IA had similar wrinkle recovery angles. The cotton fabric treated with IA, however, lost more tensile strength than that treated with PIA due to cellulose degradation. We determined the magnitude of the fabric tensile strength loss attributed to crosslinking by separating the tensile strength loss due to cellulose degradation from the total tensile strength loss, and found that the tensile strength loss caused by crosslinking for the fabric treated with PIA was significantly higher than that for the fabric treated with IA. This can probably be attributed to more concentrated crosslinkages formed on the near surface of the PIA‐treated cotton fabric. PIA had poorer penetration into the amorphous cellulose region in fiber interior due to its much larger molecular size, thus increasing its concentration on the fabric's near surface. The data also suggest that more concentrated crosslinkages on the fabric surface reduced fabric abrasion resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2023–2030, 2003

Proteases to Improve the Mechanical Characteristics of Durable Press Finished Cotton Fabrics

AbstractN‐Methylol reagents are conventional crosslinking agents that are still widely used in textile industry to produce crease‐resistant cotton fabrics. In this work serine proteases were used to recover the strength of fabrics, cross‐linked with N‐hydroxymethylacrylamide. Nearly one half of the strength loss of crosslinked cotton fabrics could be restored after protease treatment, while the wrinkle recovery angle (WRA) decreased only slightly. The enzymatic hydrolysis of the amide cross‐links in the durable pressed cellulose was confirmed by FT‐IR analysis and dyeability with an acid dye. Effect of protease concentration on the tensile strength recovery, WRA and acid dye dyeability at 30 min reaction time.magnified imageEffect of protease concentration on the tensile strength recovery, WRA and acid dye dyeability at 30 min reaction time.

Eco‐friendly durable press finishing of cellulose‐containing fabrics

AbstractTo impart easy‐care properties to cellulose‐containing fabrics along with avoiding any harmful effects of formaldehyde on both the health and the environment, attempts have been made to use citric acid (CA) as an ester crosslinking agent along with different catalytic systems in the absence and presence of certain additives. Further, fixation conditions, type of crosslinking agent, as well as type of substrate have been studied. Results revealed that the enhancement in carboxyl content, performance properties, and the decrease in tear strength (TS) as well as in whiteness indices (WI) of the finished fabric samples were increased by increasing CA concentration up to 80 g/L and by raising thermofixation temperature from 140 up to 180°C for 90 s. Inclusion of triethanolamine hydrochloride (TEA. HCl), decreased the carboxyl content, TS, color strength K/S, as well as oily stain release rating (SRR) of the finished fabric samples along with an increase in bound nitrogen (%N), wrinkle recovery angle WRA, and an improvement in WI without affecting the durable press rating (DP). Within the range examined (0–30 g/L), increasing PEG‐600 concentration improved the wet resiliency, TS, as well as WI properties of the finished samples. Increasing DMDHEU ratio in the CA/DMDHEU crosslinking system gave rise to an increase in %N, WRA (dry and wet), DP, as well as in free CH2O of finished fabrics, along with a slight improvement in WI values. On the other hand, the TS, carboxyl content, K/S, SRR values of the finished fabric samples were lower at a higher DMDHEU ratio. Increase in carboxyl content, %N, WRA (dry and wet), DP and SRR, as well as extent of post dyeing (K/S) of the treated fabric samples upon using different ester crosslinking agents followed the descending order: citric acid > pyromellitic dianhydride. The opposite holds true for the TS, and WI values. Among the esterifying catalysts used, and for a given set of finishing conditions, NaH2PO2 · H2O proved to be the most effective one, and the following order of effectiveness may be drawn: NaH2PO2 · H2O > K2HPO4 > Na3–citrate > Na2–tartrate. Inclusion of silicone softener in the finishing formulation brought about an improvement in softeness degree, WRA, %N, DP, TS as well as K/S values along with a decrease in carboxyl content, SRR, and WI values of the treated fabric samples, regardless of the used silicone softener.The performance properties of the finished fabric samples were determined by the type and nature of the substrate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2243–2253, 2002

Dimensional and Surface Properties of Plasma and Silicone Treated Wool Fabric

To improve the dimensional properties of wool fabric, two kinds of silicone polymers are applied to plasma pretreated wool. With this treatment, hygral expansion increases slightly but still remains smaller than that of silicone treated wool without the plasma pretreatment. The wrinkle recovery angles of wool increase with the treatment, and the values of fabric treated with plasma and silicone polymers are higher than those with no plasma pretreatment. In addition, the harsher handle imparted by plasma modification is improved with silicone treatment. The results show that the plasma pretreatment modifies the cuticle surface of the wool fibers and increases the reactivity of the wool fabric toward silicone polymers. Therefore, the combination of plasma and silicone treatments can improve the dimensional stability, wrinkle resistance, and performance properties of the wool. Surface smoothness of the treated fabrics as measured with a new evaluation system shows good correspondence with results from a KES-FB4 surface tester.

Performance improvement of nonformaldehyde wrinkle resistant finished cotton fabrics treated with dialdehydes

Additives, such as sodium perborate and borax, were examined in dialdehyde wrinkle resistant finishing of cotton. Results indicated that the whiteness index (WI) of cotton treated with dialdehyde and additive showed about 90% of WI of the untreated cotton but with decrease in wrinkle recovery angle (WRA) due to inhibition effect of these additives. Effect of additive on the WRA reduction was more prominent with glutaraldehyde than with glyoxal. Reduction in WRA of cotton treated with both dialdehydes and boron compound was minimized by simultaneous addition of formic acid in the bath. Addition of formic acid was also generally beneficial in maintaining WI retentions after 8 months storage. Furthermore, boron compounds were also effective in improving retentions of mechanical properties. By FTIR analysis the residual aldehyde group was detected on the dialdehyde-finished cotton, whereas no peak was shown by addition of boron compounds. This suggested that the residual aldehyde group was a main cause of fabric yellowing on the dialdehyde-finished cotton. Dialdehyde with boron compound, therefore, can be used to replace a conventional formaldehyde-containing wrinkle resistant finishing of cotton.

Two‐step durable press treatment of cotton fabric

In this paper cotton fabrics were treated by two different methods with polycarboxylic acids (citric acid and butanetetracarboxylic acid) for durable press performance. The first was a two‐step method in which the fabric was initially treated with citric acid and then treated by butanetetracarboxylic acid. The other was a mixed method in which the fabric was treated with a solution containing the two mixed polycarboxylic acids. Following the treatments, the wrinkle recovery angle, strength and strength retention of the resulting fabric were measured and compared.

Durable press finish of cotton/polyester fabrics with 1,2,3,4‐butanetetracarboxylic acid and sodium propionate

AbstractSodium hypophosphite (SHP) is widely used as an effective catalyst for the esterification reaction of cellulose with 1,2,3,4‐butanetetracarboxylic acid (BTCA). However, catalysts containing phosphorus cause significant shade changes in dyed fabrics because of their reductive nature, and the effluents containing phosphorus cause eutrophication in rivers and lakes. Hence, their commercial application as catalysts in textile processing is limited. In this study sodium propionate and its catalytic activities as a nonphosphorous catalyst were investigated. The evidence for esterification and crosslinking of cellulose with BTCA in the presence of sodium propionate was shown by an improved wrinkle recovery angle and durable press rating of treated fabrics. The presence of ester groups in the treated fabrics was confirmed by FTIR analysis. The performance of sodium propionate as a catalyst for BTCA was comparable to that of SHP. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 654–661, 2001

Nonformaldehyde Crease-Resistant Finishing of Ramie with Glyoxal in the Presence of a Swelling Agent

The feasibility of glyoxal treatment for ramie fabric in the presence of a swelling agent is studied. Adding polyethylene glycol (PEG) 600 or a higher molecular weight PEG to the glyoxal finishing bath provides an optimum balance between the wrinkle recovery angle and strength retention by maximizing ramie swelling during the crosslinking reaction. Adding PEG also increases the water of imbibition, moisture regain, whiteness index, and color strength of treated ramie fabrics. The durability of glyoxal finished fabric in the presence of PEG is also acceptable during multiple launderings. Therefore, glyoxal treatment with PEG can be used for crease-resistant finishing of ramie and ramie-blended fabrics to obtain superior performance properties.

Cotton Fabric Strength Loss from Treatment with Polycarboxylic Acids for Durable Press Performance

In this study, cotton fabrics are treated at different curing temperatures with different concentrations of 1,2,3,4-butanetetracarboxylic acid (BTCA) catalyzed with sodium hy pophosphite (SHP). Strength retention and wrinkle recovery angle (WRA) are tested, and the results show that high curing temperature and high BTCA concentration will reduce fabric strength and increase WRA. Regression models show that WRA has a close negative linear relation with the strength of the treated fabric. Both WRA and fabric strength are closely related with curing temperature and BTCA concentration. When the treated samples are further treated with 3% sodium hydroxide solution, fabric strength recovers in differing degrees and WRA decreases to the level of the control sample. Recoverable strength is assumed to be mostly induced by intramacromolecular crosslinking in the fibers, and unrecoverable strength is assumed to be due to the acidity of the treatment solution. The ratio of recoverable to unrecoverable strength shows that when curing temperature is around 160°C, strength loss due to the acidity of the treating solution is minimized.

Modification of jute by some low molecular weight glycols and a polyol under thermal treatment

Jute fabric/yarn was modified by chemical treatments using ethylene glycol (EG), diethylene glycol (DEG), polyethylene glycol (PEG) of two varieties (PEG400 and PEG1500) and poly(vinyl) alcohol (PVA) in the presence of Al 2(SO 4) 3 as the catalyst employing a pad-dry-cure technique. Controlled prior oxidation of the cellulosic and related chain molecules of jute to dialdehyde and related moieties with the help of aqueous NaIO 4 then enhancing its copper number from 2.3 to 10–13, produced optimum effects considering property improvements. Treatments of oxy-jute so obtained with 8% of the above diol/polyol modifying agents in the presence of 5% Al 2(SO 4) 3 as the catalyst, followed by drying at 95°C for 5 min and curing of the dried fabrics at 125°C for 5 min produced most balanced improvements in the textile related properties such as flexibility as revealed by bending length, wrinkle recovery angle, abrasion resistance, fiber shedding, hairiness, retention of mechanical properties and surface reflectance/gloss. Use of PVA tends to make the fabric somewhat more stiff, which can, however, be satisfactorily controlled if the PVA used is subjected to prior degradation using aqueous NaIO 4. Modification of jute by optimum dose of PEG1500 produced the most improved and balanced effects including notable improvements in tenacity and elongation at break and hence in resilience, feel and texture and substantial lowering in hairiness, bending length and fiber shedding character. Differences in the surface modification of jute fibers effected by use of different glycolic/polyol modifying agents as revealed by scanning electron micrographs have also been discussed.

Evaluating Ester Crosslinking of Cotton Fabric by a Polycarboxylic Acid Using Acid-Base Titration

Polycarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid (BTCA) have been the most promising nonformaldehyde durable press finishing agents to replace the traditional N-methylol reagents. High levels of smooth fabric appearance are the direct result of ester crosslinking of cotton cellulose by a polycarboxylic acid, and appearance is therefore determined by the amount of ester crosslinks formed on the fabric. In this research, we use acid-base titration to evaluate ester crosslinking by measuring the concentrations of the ester and the free carboxylic acid and the percent of carboxyl groups forming crosslinks on the cotton treated with BTCA. We correlate the wrinkle resistance of the treated cotton with the ester concentration on the fabric. The linear correlation between wrinkle-recovery angle and ester concentration indicates that ester concentration determined by titration can be used as the basis for evaluating the effectiveness of crosslinking for durable press finished cottons.

Evaluating Glutaraldehyde as a Nonformaldehyde Durable Press Finishing Agent for Cotton Fabrics

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.

Mechanical Strength of Durable Press Finished Cotton Fabric

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.

Durable Press Finishing of Cotton Fabrics by Polycarboxylic Acids After Graft Copolymerization with Hydroxyethyl Methacrylate

The effects of cotton fabric grafting with hydroxyethyl methacrylate (HEMA) and treatment with polycarboxylic acids (BTCA and CA) are studied. FTIR analysis confirms the successful graft copolymerization of HEMA onto cotton fabrics. Moisture regain decreases as the graft add-on increases, but the mechanical properties and wrinkle recovery angle (WRA) do not show great changes. After introducing many more hydroxyl groups from the HEMA into the cotton cellulose, BTCA shows much better effects on DP treatment. The WRA of the grafted fabrics can be improved to 148° from 116° of the control fabric treated by BTCA but without pretreatment by graft copolymerization. However, this good result is not observed with the CA treatment. All samples with and without pretreatment by graft copolymerization show the same strength loss after DP treatment.

The study of rapid curing crease-resistant processing on cotton fabrics. Part I. The effect of chitosan on the physical properties of processed fabrics

The principal aim of this study is to explore the effect of chitosan on the physical properties of cotton fabrics in rapid curing crease-resistant processing. It was determined that compared with the traditional three-stage processing, the addition of chitosan is beneficial to the absorbency of processed fabrics, dry-wet wrinkle recovery angle, and tensile strength retention. In addition, the dry-wet wrinkle recovery angle of processed fabrics increases with the increase of curing temperature and curing treatment time, but absorbency and tensile strength retention both decrease. Also, the dry-wet wrinkle recovery angle and tensile strength retention of processed fabrics increase with higher chitosan concentrations, but the fabric's absorbency is reduced. In general, use of 0.5%≈0.75% chitosan with DMEU curing treatment conditions of 8%, 200°C for 30 s will provide optimum physical property balance for processed fabrics. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 35–40, 2000

Polymeric multifunctional carboxylic acids as crosslinking agents for cotton cellulose: Poly(itaconic acid) andin situ polymerization of itaconic acid

Multifunctional carboxylic acids have been used as nonformaldehyde durable press finishing agents for cotton. In previous research we found that maleic acid (MA) and itaconic acid (IA) polymerize in situ on cotton fabric at elevated temperatures when both potassium persulfate (K2S2O8) and sodium hypophosphite (NaH2PO2) are present, thus imparting wrinkle resistance to the treated cotton fabric. We also found that MA and IA polymerize in aqueous solutions in the presence of K2S2O8 and NaH2PO2. In this research, we compared the effectiveness of poly(itaconic acid) (PIA) applied to cotton fabric as a polymer and IA applied as a monomer and allowed to polymerize in situ for crosslinking cotton cellulose. We found that IA is more effective in esterifying cotton cellulose and imparting a high level of wrinkle resistance to the fabric as it polymerizes in situ than PIA applied as a polymer. We also found that tensile strength loss of the cotton fabric crosslinked by IA polymerizing in situ as a function of fabric wrinkle recovery angle is practically the same as that crosslinked by PIA applied as a polymer. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 319–326, 2001

Characterization of cotton fabrics treated with glyoxal and glutaraldehyde

Comparison was made for glyoxal- and glutaraldehyde-treated cotton fabrics. Crosslinking efficiency between cellulose and dialdehyde measured by wrinkle recovery angle was higher with glutaraldehyde than with glyoxal. This disparity was presumably due to different forms of two dialdehydes in aqueous solution that were confirmed by FTIR and UV-visible spectroscopies. Such difference in hydrated forms along with easy formation of oligomeric and polymeric forms in glyoxal could influence on sorption and reactivity of the dialdehydes with cellulose. Staining and water imbibition values and various thermal parameters, such as percent residue, differential thermogravimetric peak temperature, and maximum rate of weight loss, also supported high crosslinking efficiency of glutaraldehyde. The presence of unreacted aldehyde groups within the treated fabrics was confirmed by FTIR analysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2691–2699, 1999