Surface modification of polyester fabrics by enzyme treatment

In this study, the effect of enzymatic hydrolysis using lipase and cutinase on poly(ethyleneterephthalate) (PET) fabrics was investigated in an attempt to improve the hydrophilicity of these fabrics. The hydrolytic activity of the enzymes was expressed for variations in pH levels, temperatures, enzyme concentrations, and treatment times. The effects of using a nonionic surfactant were examined by measuring moisture regain and surface wettability. Finally, the fabric characteristics that were affected by enzyme treatment were evaluated by tensile strength and scanning electron microscopy. The optimal treatment conditions for lipase were determined to be a pH of 4.2, a temperature of 50 °C, a lipase concentration of 100 %, and a treatment time of 90 min; those for cutinase were determined to be a pH of 9.0, a temperature of 50 °C, a cutinase concentration of 100 %, and a treatment time of 60 min. At optimal enzymatic treatment conditions, we got the significant results of increase on the moisture regain and the water contact angle (WCA) and water absorbency effectively decreased. Triton X-100 facilitated cutinase hydrolysis on PET fabrics; however, it was ineffective for lipase. With enzymatic treatment, the tensile strength did not decrease.     

Optimization of enzymatic treatment of polyester fabrics by lipase from <Emphasis Type="Italic">Porcine Pancreas</Emphasis>

The aim of this study was to provide the optimum condition for improving the hydrophilicity of PET fabrics by lipase treatment. The lipase hydrolytic activity, moisture regain, and wettability of PET fabrics were measured at different pH, temperature, reaction time, and concentration. The hydrolytic activity of lipase was evaluated by the number of carboxylic groups, using the titration method. Each treatment condition was controlled by measuring the hydrolytic activity, moisture regain, and wettability. The lipase treatment condition was controlled at pH 7.5, temperature 40 °C, treatment time 90 min, and concentration 6.25 g/l. Lipase treatment was an effective method to improve the moisture regain and wettability of PET fabrics because lipase hydrolysis formed hydrophilic groups on the surface of PET fabrics. The surface of the lipase-treated PET fabrics showed cracks and voids, largely responsible for the increase in the PET’s water-related properties. The nitrogen contents of the lipase-treated PET fabrics were measured at only 0.072 %. Thus, the improvement of the surface wettability of the lipase-treated PET surface was associated with the hydrolytic action of lipase rather than with protein absorption.     

Optimization of papain treatment for improving the hydrophilicity of polyester fabrics

The goal of this study was to establish optimal conditions for improving the hydrophilicity of polyester fabrics. The hydrolytic activity of papain was determined by measuring the number of carboxylic groups in the treatment solution. Papain treatment conditions-such as pH, temperature, treatment time, and enzyme concentration-were optimized by measuring hydrolytic activity, moisture regain, and wettability. Optimal papain treatment conditions were identified as a pH of 7.5, temperature of 30 °C, treatment time of 60 min, and papain concentration of 100 %(o.w.f.). The moisture regain for polyester fabrics treated with papain improved to 1.28±0.02 %, a 2.7-fold increase compared to that of untreated polyester fabrics. As the hydrolytic activity increased, the moisture regain and wettability of the treated fabrics improved. L-cysteine and sodium sulfite did not affect the moisture regain of papain-treated polyester fabrics.     

Improvement of hydrophilicity of polylactic acid (PLA) fabrics by means of a proteolytic enzyme from <Emphasis Type="Italic">Bacillus licheniformis</Emphasis>

Polylactic acid (PLA) has received considerable attention as a biomass material for the textile industry. To use a PLA fabric in the textile industry, suitable postprocessing that can promote hydrophilicity of such fabrics is required. Here, hydrolytic action of a proteolytic enzyme (alcalase from Bacillus licheniformis) on PLA fibers was evaluated. In addition, the effects of an additive on the enzymatic hydrolysis were analyzed. The results revealed that the optimal enzymatic-hydrolysis conditions for this alcalase are pH 9.5, temperature 60 °C, enzyme concentration 50 % on weight of fabric (owf), and Lcysteine concentration of 3 mM. PLA fabrics were hydrolyzed effectively, however; there was no damage to these fabrics judging by tensile strength and surface observations. X-ray diffractometry identified a new peak (at 2θ=18.5 °), implying a morphological change caused by the treatment. Moreover, hydrophilic properties such as moisture regain and dyeing properties were enhanced by this proteolytic enzymatic hydrolysis. Therefore, according to this study, enzymatic hydrolysis is a suitable finishing method for improvement of hydrophilicity of PLA fabrics.     

Lipase treatment of polyester fabrics

The aim of this paper is to improve moisture regain of PET fabrics using a lipase treatment. Effects of nine lipase sources, lipase activator and nonionic surfactant on moisture regain of PET fabrics are examined. Moisture regains of lipase-treated samples improve by two times in average compared with untreated and buffer-treated samples. Alkaline treatment creates larger pitting by more aggressive attack into fiber which is proved by SEM and water contact angle measurement. Moisture regain by alkaline treatment (0.568 % ± 0.08) does not improve. However, lipase-treatment (L2 treatment) improves moisture regain up to 2.4 times (1.272 % ± 0.05). Although lipase treatment is more moderate than alkaline treatment, lipase hydrolysis on PET fabrics improves moisture regain, efficiently. K/S values improved confirm that carboxyl and hydroxyl groups are produced on the surface of PET fabrics by lipase hydrolysis. Moisture regain and dyeability improve by lipase hydrolysis on PET fabrics.     

A novel method to analyze the moisture liberation of textile fabrics

In this paper, a purpose-built apparatus was used to analyze the moisture liberation of textile fabrics. Fabrics were wetted and placed in an air-conditioned room to test the variation of weight and surface temperature during the process of moisture liberation. Effects of textile materials and fabric structures on the velocities of moisture liberation of fabrics were analyzed; the temperature variation and its relationship with moisture regains of fabrics in the moisture liberation were also studied. Moisture liberation velocities of polyester and silk fabrics are much higher than that of wool and cotton fabrics. For the same textile materials, knitted fabrics absorbed more water and thus took longer time to liberate the water. The surface temperature of fabrics showed three stages during moisture liberation. With the decrease of moisture regain, fabric temperature decreased gradually and jumped quickly to ambient temperature. In this way we could evaluate the moisture desorption of fabrics and develop quick-drying fabrics with imporved moisture and thermal properties.     

A new catalyst for glyoxal durable press finish of cotton fabrics

Aluminum ammonium sulfate was used as a new catalyst for glyoxal to minimize the decrease of physical properties of durable press cotton fabrics, and the optimum treatment conditions such as the concentration of glyoxal, molar ratio of catalyst to glyoxal, curing temperature and time were investigated. The retention of tensile strength and the whiteness of fabrics treated with glyoxal/aluminum ammonium sulfate was increased as much as to the degree of that obtained with glyoxal/aluminum sulfate while wrinkle recovery angles were as good as those of the latter. Some additives such as DEG, polyurethane and softener were used to improve the physical properties. When DEG or polyurethane was added to the glyoxal padding solution, wrinkle recovery angle (WRA) significantly increased while tensile strength and whiteness were not influenced. DEG added to the glyoxal padding solution increased the durability of DP finish. The softener added to the glyoxal padding solution increased the WRA of treated fabrics while it decreased the tensile strength slightly. The whiteness of fabrics treated with glyoxal alone increased while the WRA decreased slightly.     

Tertiary Amination/Hydroxypropylsulfonation of Cornstarch to Improve the Adhesion-to-Fibers and Film Properties for Warp Sizing

To investigate the effects of tertiary amination/hydroxypropylsulfonation on the adhesion-to-fibers and film properties of corn starch for warp sizing, a series of tertiary aminated and hydroxypropylsulfonated corn starch (TAHPSS) samples were prepared by the tertiary amination and hydroxypropylsulfonation of acid-hydrolyzed corn starch (AHS) with 2- dimethylaminoethyl chloride hydrochloride (DMC-HCl) and 3-chloro-2-hydroxy-1-propanesulfonic acid sodium salt (CHPS-Na) simultaneously. The adhesion was evaluated by measuring the bonding force of starch to the fibers. The film properties were investigated in terms of tensile strength, breaking elongation, degree of crystallinity, and moisture regain. The results showed that tertiary amination/hydroxypropylsulfonation was able to increase bonding forces of starch to cotton and polyester fibers, enhance breaking elongation and moisture regain of the starch film and to decrease the tensile strength and degree of crystallinity of the film, thereby improving the adhesion and reducing film brittleness. Increasing the level of tertiary amination/hydroxypropylsulfonation was favorable for gradually improving the adhesion and decreasing the brittleness. The TAHPSS showed potential for use in cotton warp sizing.     

A study of physical modification on grey cotton by laser irradiation

The surface morphology of the CO₂ laser treated grey cotton fabrics was studied which showed a characteristics sponge-like structure on cotton fibres after treating with CO₂ laser irradiation. The laser treatment parameters ranging from 100 to 150 pixel time and 40 to 70 dot per inch (dpi) were irradiated on the grey cotton fabrics directly and the degree of physical modifications, such as surface morphology, wettability and fabric strength, were changed accordingly with various laser treatment parameters. The surface morphology, wettability and tensile strength of cotton fibre treating with laser were evaluated using different instruments, such as Scanning Electron Microscope (SEM), contact angle meter and tensile strength machine. In spite of creating a sponge-like structure on fibre surface after treating with laser, the wettability of the samples was highly improved but the tensile strength was decreased.     

Transfer printing with disperse dyes on cotton fabric modified with an aqueous tolylene diisocyanate derivative

Transfer printing with disperse dyes on cotton fabric modified with an aqueous tolylene diisocyanate derivative (TDD) was discussed in this paper. The effect of the degree of substitution (DS) on color strength (K/S value) of the modified and transfer printed fabric was investigated. The DS of the cotton fabric increased with increases in TDD concentration and curing temperature and time, while the sample whiteness decreased with the increasing curing temperature and time. And the change of structure of the modified cotton fabric was characterized by FT-IR spectra, DSC curves, and SEM images. All of the factors, such as the concentration and molecular weight of poly(ethylene glycol), the DS of the modified fabric, the transfer printing temperature and time would affect the K/S value of the sample. After transfer printing with disperse dye, the K/S value and printing fastness of TDD-modified cotton fabric were higher than those of cotton control fabric, the change of chromatic difference was not obvious, but the tensile strength of the modified fabric was lower than that of original cotton.     

Optimization of enzymatic treatment of polyamide fabrics by bromelain

In this study, we investigated the effects of enzymatic hydrolysis on polyamide fabrics by using bromelain as an enzyme. The hydrolytic activity of bromelain was evaluated on the basis of the number of carboxylic groups formed on the surface of the polyamide fabrics, and it was measured using the reactive dye absorbance. In addition, 2,4,6-trinitrobenzenesulfonic acid was added as an indicator to measure the number of amino groups released into the treatment liquid by the changes in color of the liquid. The optimum treatment conditions were bromelain pH of 6.0, treatment time of 120 min, temperature of 50 °C, concentration of 10 % (owf), and L-cysteine concentration of 70 mM. The weight loss in the fabric after treatment with bromelain facilitated by L-cysteine significantly improved; however, the tensile strengths of the polyamide fabrics did not show any differences. Bromelain hydrolysis of the polyamide fabrics thus improved hydrophilicity without damaging the fabrics’ strength.     

A novel approach for estimating the relation betweenK/S value and dye uptake in reactive dyeing of cotton fabrics

This paper focuses on the application of a novel mathematical limit approach derived forK/S values in reactive dyeing of cotton fabrics. The relation obtained from Kubelka-Munk equation is used because the Kubelka-Munk equation is the basic relationship among fabric reflectance, fabric dye content and dyestuff characteristics. The limit approach derived in a former paper is applied to the laboratory dyeings and the dyeing behavior of some reactive dyes on cotton knitted fabric has been obtained. The results of the laboratory experiments are discussed using the new mathematical approach. When the actualK/S values obtained from the dyeings and the calculatedK/S values derived by the limit approach are considered independently, it is observed that the limit relation is valid for low dye concentration applications. When theK/S values are calculated taking theK/S value of the initial dyeing concentration (0.1 % owf) as the starting concentration by applying the result of the derived limit approach, the calculatedK/S values fit with the ones obtained in actual dyeings. It is concluded that the novel approach presented in the paper can be used in calculating theK/S values when the initial dyeings at low dye concentrations are carefully carried out.     

The eco-friendly surface modification of textiles for deep digital textile printing by in-line atmospheric non-thermal plasma treatment

This study evaluated the potential application of an atmospheric plasma (AP) treatment as a pre-treatment for digital textile printing (DTP) of polyester (PET) fabrics and cotton, in order to determine its viability as an alternative to the usual chemical treatment. The surface properties of the AP-treated fabrics were examined through scanning electron microscopy (SEM) and contact angle, and the physical properties, such as electrostatic voltage and water absorbance, were tested. The properties of cotton and PET with the AP treatment were found to be dependent on number of repetitions and electric voltage. Although no remarkable surface differences were observed by SEM in the fabrics before and after treatment, the static contact angle of the PET after AP treatment was decreased from 85 ° to 24 ° at wave. In addition, the charge decay time decreased as the voltage and number of treatments increased. The absorption height of PET changed after exposure to 7 mm with increasing measurement time. The K/S with and without the AP pre-treated and DTP finished cotton was better than that with the usual chemical modification. In PET, the 0.5 kW and 1 time AP-treated specimen showed the highest K/S values.     

Effect of pigment particle character on dyeing performance of cotton fabrics

The cotton fabrics were dyed by exhaust method using the pigment dispersions as colorant, and meanwhile the effects of particle character on dyeing performance were further investigated. The results showed that the larger zeta potentials, the higher K/S value, pigment uptakes, rubbing and washing fastness of the dyed cotton fabrics were. Adsorption isotherms were belonging to Langmuir type when zeta potentials were about 0.46 mV and 31.39 mV respectively. The cotton fabrics that dyed by the pigment dispersions with small particles had high K/S value, rubbing and washing fastness. The chemical structure of pigment had little influence on pigment uptakes, and all kind of pigment dispersions reach to 98 % uptakes after 30 min but exhibit various uptake rates at initial stage.     

A new model substrate for cutinase hydrolyzing polyethylene terephthalate

This study aimed at comparatively investigating the enzymatic hydrolysis of a new model substrate water-soluble polyester (WSP) and polyethylene terephthalate (PET) with cutinase. The changes of WSP solution properties were investigated by measuring pH value, alkali consumption, and specific viscosity. The results indicated that pH value of enzymatically treated WSP solution was decreased, causing an increase in alkali consumption. The decreases in specific viscosity and the glass transition temperature (T _g ) of WSP treated with cutinase indicate the decrease in its molecular weight as demonstrated in gel permeation chromatography analysis (GPC). Cutinase treatment resulted in an improvement of the hydrophilicity of PET fabrics, which was determined by dye uptake and water contact angle.     

A study on combining natural dyes and environmentally-friendly mordant to improve color strength and ultraviolet protection of textiles

In this study, natural dyes were extracted from five plants, namely diospyros kaki, dioscorea cirrhosa, millettia (jixueteng), ecliptae, and macrocarpa nucuma, using environmentally-friendly solvents, including ethanol and deionized (DI) water. A plant mordant, tannin extracted from Emblica officinalis G., and a metal mordant, copper sulfate, were used in the pre-dyeing process. Cotton and silk fabric samples were treated using the five natural dyes without and with mordanting for comparison on their color strength and characteristics as well as protection against ultraviolet radiation (UVR). Results revealed that Emblica officinalis G. had the highest total phenol content, followed by dioscorea cirrhosa. The presence of abundant phenolic groups in the natural dyes and mordant makes them effective coloration agents for fabrics. Cotton and silk fabrics dyed using ecliptae without pre-mordanting had the highest K/S values. Silk fabrics had higher K/S values than cotton fabrics, indicating greater color strength in pre-mordanted silk treated with DI water-extracted dyes. Natural mordant used before treatment with natural dyes contribute to significant enhancement in color strength, and Emblica officinalis G. alone could darken the color of cotton and silk fabrics dyed with plant pigment. Moreover, treatment with natural dyes after mordanting can increase ultraviolet protection factor (UPF) and the enhancement in UVR protection is greater and more significant in cotton fabrics than in silk fabrics, and in fabrics treated with DI water-extracted natural dyes than in those treated with ethanol-extracted ones. In conclusion, pre-dyeing with natural mordant followed by treatment with natural dyes extracted using environmentally-friendly solvents can enhance significantly K/S and UPF, offering directions for manufacturing textiles without environmental hazards but with good appearance and health benefits.     

Using artificial neural network to predict colour properties of laser-treated 100% cotton fabric

In this paper, artificial neural network (ANN) model was used for predicting colour properties of 100 % cotton fabrics, including colour yield (in terms of K/S value) and CIE L, a, and b values, under the influence of laser engraving process with various combination of laser processing parameters. Variables examined in the ANN model included fibre composition, fabric density (warp and weft direction), mass of fabric, fabric thickness and linear density of yarn (warp and weft direction). The ANN model was compared with a linear regression model where the ANN model produced superior results in prediction of colour properties of laser engraved 100 % cotton fabrics. The relative importance of the examined factors influencing colour properties was also investigated. The analysis revealed that laser processing parameters played an important role in affecting the colour properties of the treated 100 % cotton fabrics.     

Performance of cotton fabric treated with an amino-terminated hyperbranched polymer

An amino-terminated hyperbranched polymer (HBP-NH₂), synthesized from methyl acrylate and diethylene tri-amine by polycondensation, was applied to treat cotton samples by a pad-dry-cure method. Physical properties, salt-free dye-ability, antimicrobial activity, and antiultraviolet property of the treated cotton samples were tested. The crystallinity and mechanical properties, including breaking strength, breaking elongation, and Young’s modulus of the treated cotton fibers, increased slightly in comparison with those of the untreated cotton fibers. The thermal stability and the moisture regain were also improved slightly. Dyed with direct dyes and reactive dyes in the absence of the electrolytes, the treated cotton fabric showed similar or higher color strength compared with the untreated cotton fabric in conventional dyeing. The treated cotton fabric can also be dyed with acid dyes effectively. In addition, the treated cotton fabric showed good antimicrobial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The study of the antiultraviolet properties of the treated cotton fabric indicated that the HBP-NH₂ contributed to the reduction of UV transmission and the increase of UPF.     

Dimensional and physical properties of plain knitted fabrics made from 50/50 bamboo/cotton blended yarns

In this study, the dimensional and some physical properties of plain knitted fabrics made from 50/50 bamboo/cotton blended yarns are investigated. In order to see the differences and similarities, the results are then compared with those for similar fabrics knitted from 50/50 conventional viscose/cotton and 50/50 modal/cotton blended yarns. Each fabric type was produced with three different stitch lengths. After all fabrics were dyed under identical dyeing conditions, they were subjected to dry and full relaxation treatments. For dimensional properties of fabrics, course, wale and stitch densities were measured. Then, by calculating statistically best-fit lines passing both through the experimental points and the origin, dimensional constants i.e. k values were predicted in terms of the fiber types. The result show that each fabric type knitted from bamboo/cotton, viscose/cotton and modal/cotton blended yarns behaves in a similar manner. However, in both dry and fully relaxed states, the modal/cotton knitted fabrics tend to have slightly higher k values than the bamboo/cotton and viscose/cotton knitted fabrics. For physical properties, fabric weight per unit area, thickness, bursting strength, air permeability and pilling were evaluated. The results show that the weight, thickness and air permeability values are independent of the fiber type. Plain knitted fabrics from modal/cotton blended yarns have the highest bursting strength values. Plain knitted fabrics from bamboo/cotton blended yarns tend to pill less.     

Development of biofunctional textiles by the application of resveratrol to cotton, bamboo, and silk

The goal of this work was to create a new generation of greener fabrics made of natural materials. For that, resveratrol (Res), obtained from Polygonum cuspidatum extract and known to have antibacterial, antifungal, and anti-inflammatory activity, was applied by an exhaustion method to cotton, bamboo, and silk knit fabrics. The fabrics adsorption behavior was tested and the amount of Res adsorbed was determined by its decrease on the immersion solutions with time and measured by spectrophotometry at 350 nm. The maximum adsorption capacity was observed for silk and it was independent of pH conditions used (50.5 % at pH=7 and 58.3 % at pH=5 of the initial Res concentration). At acidic pH conditions, cotton adsorbed 51.2 % of Res and Bamboo adsorbed only 28.1 % in 15 min. However, neither cotton nor bamboo adsorbed Res at pH=7. The release behavior was also analyzed and the highest Res release was observed for cotton in alkaline sweat and urine mimic solutions. The lowest release was achieved by cotton in water (1.0 ng/ml). Moreover, no relation was found between the amounts of Res adsorbed or released and cell viability. In conclusion, this work shows that it is possible to obtain cotton, bamboo, and silk functionalized with resveratrol. The incorporating process here described is simple and silk-Res can be presented as a good combination.