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.     

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.     

Cutinase treatment of cotton fabrics

Our study proposes an enzymatic scouring method for cotton fabrics using the enzyme cutinase. We established cutinase treatment conditions for cotton fabrics from their relative activity at different pH levels, temperatures, enzyme concentrations, and treatment times. Weight loss, moisture regain, K/S value, tensile strength, and SEM micrographs of cotton fabrics were analyzed. We determined the optimum cutinase treatment conditions to be as follows: pH of 9.0, temperature of 50°C, cutinase concentration of 100 %, and a treatment duration time of 60 min. We discovered that this cutinase treatment hydrolyzed the cuticle of cotton fabrics. The cutinase treatment did not decrease the moisture regain and the K/S value. The optimum concentrations of Triton X-100 and calcium chloride, which were used as auxiliaries for cutinase treatment, were found to be 0.5 % (v/v) and 70 mM, respectively. Some cracks were observed on the surface of the cotton fibers; however, the tensile strength did not decrease.     

Evaluating antistatic performance of plasma-treated polyester

Use of low temperature plasma treatment has been attempted in the textile industry and there the has been some success in the dyeing and finishing processes. In this paper, an attempt was made to apply low temperature plasma treatment to improve the antistatic property of polyester fabric. The polyester fabrics were treated under different conditions with low temperature plasma. An orthogonal array testing strategy was employed for obtaining the optimum treatment condition. After low temperature plasma treatment, the polyester fabrics were evaluated with different characterization methods. Under the observation of scanning electron microscope, the surface structure of the polyester fabric treated by low temperature plasma was found to be seriously altered which provided more capacity for polyester to capture moisture and hence increased the static charges dissipation. The relationship between moisture content and half-life decay time for static charges was studied and the results showed that the increase in moisture content would result in shortening of the time for static charges dissipation. Moreover, the antistatic property of the low temperature plasma treated polyester fabric was greatly improved. In addition, the antistatic property of the polyester fabric treated by low temperature plasma was compared with that of the polyester fabric treated with a commercial antistatic finishing agent.     

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.     

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.     

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.     

A comparative evaluation of the action of savinase and papain to the cutinase-pretreated wool

The enzymatic anti-felting of wool with proteases is a promising eco-friendly alternative to the chlorine-Hercosett process. However, protease molecules could penetrate into the interior of fibers during wool processing, easily causing unacceptable damages. In this paper, the action and mechanism of two protease treatments, i.e. Savinase and papain treatments on the properties of cutinase-pretreated wool fabrics were investigated and compared. The results showed that the anti-felting processing based on cutinase and papain treatments seemed more effective. When the percentages of weight loss for the combined treated fabrics were similar, the improvement of wettability and shrink-resistance for the cutinase-papain treated sample was more remarkable, the strength loss was also lower than that of the sample treated with cutinase and Savinase consecutively. The mechanisms of the two different combined treatments were further evaluated by Allwöden’s reaction and amino acid analysis. The comprehensive comparison proved that the hydrolytic activity of papain towards the scale exocuticle of wool was a bit higher than that of Savinase and less degradation of the interior of fibers occurred during the cutinasepapain treatment.     

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.     

Effect of drying condition on the electrostatic characteristics of the laundry

This paper suggests the optimal conditions to prevent electrostatic charge in the laundry by the evaluation of the electrostatic characteristics during the drying process. Cotton, nylon, and polyester fabrics were used as test specimens, employing the standard washing cycle. The electrostatic characteristics of the laundry were measured after the automatic drying process. This paper investigates the optimal conditions for preventing electrostatic charges in laundry by evaluating the electrostatic characteristics that occur during the drying process. Cotton, nylon, and polyester fabrics were used as the test specimens, employing a standard washing cycle. The electrostatic characteristics of the laundry were measured immediately after the automatic drying process. The results, showed that the moisture content decreased and the electrostatic charge increased with drying time. The specimen fabrics had already dried up before completion of the standard drying cycle. Consequently, the excessive drying generated an electrostatic charge due to removal of the traces of remaining moisture and the resulting excessive friction. For cotton fabrics, the electrostatic charge was under 1000 V even for the maximum drying time due to the intrinsic high moisture regain of cotton. On the other hand, the electrostatic charge produced for nylon fabrics increased rapidly with the drying time, and amounted up to approximately 8000V after 120 minutes. The results also indicated that the electrostatic charge could be decreased by drying fabrics of only one kind. When mixed kinds of fabrics were dried, the electrostatic charge increased remarkably. Therefore, it is suggested that laundry be classified and washed according to the kinds of fiber, and not be dried excessively to reduce electrostatic charge. In addition, the proper use of a softener is effective in reducing the electrostatic charge.     

Polyester modification through synthesis of copper nanoparticles in presence of triethanolamine optimized with response surface methodology

In this paper, polyester fabric was modified through synthesis and fabrication of Cu/Cu₂O nanoparticles using a facile and cost-effective method at boil by chemical reduction through exhaustion route. Triethanolamine (TEA) was used for aminolysis of polyester fabric and pH adjusting, copper sulfate (CuSO₄) as metal salt, sodium hypophosphite (SHP) as reducing agent and polyvinylpyrrolidone (PVP) as stabilizer. A response surface methodology was also employed to optimize the reaction conditions and study the effects of SHP, PVP and TEA concentrations in the processing. The images of field-emission scanning electron microscopy (FESEM), the patterns of energy-dispersive spectroscopy (EDX) and X-ray diffraction (XRD) patterns confirmed successfully synthesis of Cu and Cu₂O nanoparticles on the polyester fabric. Further, the thermal behavior of the untreated and treated fabrics was studied by using thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC). The treated fabrics indicated good properties regarding wettability and flame-retardant along with high tensile strength.     

Effectiveness of flavourzyme treatment on polyamide fabric

We characterized the effectiveness of Flavourzyme treatment in the hydrolysis of amide bonds in polyamide fabric by quantitating the ionic groups released into the treatment liquid and those formed on the fabric surface. On the basis of hydrolytic activity, we demonstrated that Flavourzyme effectively hydrolyzed amide bonds in polyamide (PA) fabric. The optimal treatment conditions were found to be pH 7.0, temperature 40 °C, treatment time 120 min, and Flavourzyme concentration 10 % based on weight of fiber. PA fabric treated with Flavourzyme exhibited increased numbers of amino and carboxyl groups, as evaluated by zeta potential and color strength. As the amounts of ionic groups formed by Flavourzyme hydrolysis increased, the water contact angle and water absorbency time decreased.     

Transglutaminase treatment for improving wool fabric properties

The microbial transglutaminase (mTGase) is used as a bio-catalyst to repair the wool damages caused by chemical or enzymatic treatments. In this paper, the effect of mTGase on the degree of yarn strength, area shrinkage, wettability, and the dyeing properties of wool was investigated. Through mTGase treatment, the yarn strength was improved about 22.2 %. The knitted wool fabrics treated with mTGase after pretreatment of H₂O₂ and protease displayed 7.5 % of area shrinkage and about 22.3 % recovery in tensile strength when compared with those treated without mTGase. Also, mTGase treatment could improve the wettability and dyeing properties of wool fabrics. With the increase of mTGase concentration, the initial dye exhaustion increased significantly and the time to reach the dyeing equilibrium was shortened. It was evident that the improvement of dyeing properties was closely related to the improvement of wettability performance of wool fabric by using transglutaminase.     

Preparation process and antimicrobial properties of cross-linking chitosan onto periodate-oxidized bamboo pulp fabric

Chitosan cross-linked bamboo pulp fabric (CCBPF) was prepared by treating the oxidized bamboo pulp fabric with the chitosan aqueous acetic acid solution. FTIR spectroscopy was used to examine the chemical bonding between chitosan and oxidized bamboo pulp fabrics, X-ray diffraction and thermogravimetry were used to detect the cellulose structure. The impact of the periodate oxidation and chitosan treatment on the physical properties of bamboo pulp fabrics was evaluated by determining the aldehyde content, weight loss, mechanical strength, wrinkle recovery angle, and moisture regain of fabrics as well as chitosan content in the composite chitosan-bamboo pulp fabrics. Antibacterial activity of the CCBPF against Staphylococcus aureus and Escherichia coli was investigated in vitro experiments. The results indicated that the aldehyde groups in the periodate oxidized bamboo pulp cellulose were reacted with the amino groups of chitosan to form Schiff base, and the resultant CCBPF displayed good wrinkle recovery angle and moisture regain. In comparison with those of the oxidized bamboo pulp fabric, the CCBPF exhibited a lower thermal stability, the crystallinity decreased from 42.73 % to 39.15 %, the mechanical strength of CCBPF had no significant change, and the CCBPF showed excellent antibacterial activity against both types of bacteria which was durable till 50 washes.     

Antistatic effect of atmospheric pressure glow discharge cold plasma treatment on textile substrates

Hydrophobic synthetic textile substrates, nylon and polyester fabrics, were continuously treated in an atmospheric-pressure-glow-discharge-cold-plasma reactor using He and air. The samples were evaluated for antistatic properties by measuring the static charge build-up and half charge decay time. The 60 sec air-plasma treated nylon fabric produced only 1.53 kV of charge and showed a significantly smaller half decay time of 0.63 sec compared to static voltage of 2.76 kV and a half decay time of 8.9 sec in the untreated nylon fabric. In comparison, the He plasma treated nylon fabrics showed relatively less improvement by producing static charge built-up of 2.12 kV and half charge decay time of 1.1 sec. Similar improvements were obtained for polyester (PET) fabrics as well. The treated samples showed good antistatic properties even after five laundry wash cycles. The surface characteristics of the samples were investigated using SEM, AFM, and ATR-FTIR. The results revealed that the improvement on antistatic properties are attributable to increase in the surface energy of the fabrics due to the formation of hydrophilic groups and increase in the surface area due to the formation of nano-sized horizontal and vertical channels on the fibre surface. The study suggests that plasma treatment may be used for imparting effective antistatic finish on otherwise hydrophobic substrates.     

Parametric study of CF4-plasma on the hydrophobicity of polyester synthetic leather

Atmospheric pressure plasma (APP) technology has been proven to be an effective method for improving the hydrophobicity of fabric surface. While many researchers have worked on apparel fabrics, polyester and synthetic leather fabrics, popular in the luxury textile market, have been examined rarely. In this regard, this paper reports the effects of APP treatment using tetrafluoromethane (CF₄) as the polymerizing monomer on hydrophobicity of polyester synthetic leather. The polyester synthetic leather samples were treated under various parameters and hydrophobicity was found to be greatly enhanced under a certain range of treatment conditions. An optimization of the treatment parameters was conducted and the results showed that a hydrophobic surface with a contact angle of 106 ° was achieved, compared to the untreated sample’s 0 °.     

Study on the Reduction Properties of Thiourea Dioxide and Its Application in Discharge Printing of Polyester Fabrics

The thiourea dioxide (TDO) was tentatively applied as a reductive discharging agent onto the discharge printing of polyester fabrics. The effect of aqueous solution temperature on the reducing capacity of TDO was thoroughly investigated by measuring oxidation-reduction potentials and hydrolysis kinetic curves. The effects of TDO on disperse dyes in aqueous solution and disperse dyes printed on the surfaces of glass substrates or polyester fabrics were investigated by analyzing the color changes before and after TDO discharge treatment. It was confirmed that TDO reduction became stronger with increasing aqueous solution temperature. TDO could destroy the chromogenic groups of the selected azo-dyes in aqueous solution and on the surfaces of glass substrates. Different from cotton and silk fabrics, the discharge effect of TDO directly depended on the compact structure of the polyester fibers. When a discharge accelerant was added into white discharge pastes with TDO, the compact structure of polyester fibers was opened up to achieve a good discharge effect. This study provides a new method for TDO development and a new strategy for the discharge printing of polyester fabrics.     

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.     

Fabrication of electromagnetic shielding polyester fabrics with carboxymethyl chitosan-palladium complexes activation

Electromagnetic shielding polyester fabrics were prepared using carboxymethyl chitosan-palladium (CMCS-Pd) complexes as activation solution, followed by electroless nickel plating. CMCS-Pd complexes were prepared by the complexing adsorption between CMCS and Pd²⁺. The effects of reaction time and pH value on the adsorption of Pd²⁺ by CMCS were discussed. The maximum adsorption capacity was calculated as 4.27 mmol/g. CMCS-Pd complexes were characterized by ultraviolet (UV) spectrophotometer and Fourier transform-infrared (FTIR) spectroscopy. The induction time of electroless plating decreased gradually with the increase of Pd²⁺ concentration. The lowest surface resistance 125 mΩ/sq of the treated polyester fabric was obtained when Pd²⁺ concentration in CMCS-Pd complex was 1.5 g/l. The prepared polyester fabrics had excellent electromagnetic shielding effectiveness (SE) of 40–60 dB. The treated polyester fabrics were also characterized by scanning electron microscopy (SEM). Results showed that CMCS-Pd was effective to form an active catalyzed layer on polyester substrate and the 1.5 g/l Pd²⁺ was sufficient to initiate electroless nickel plating reaction. The CMCS-Pd complex activation and electroless nickel plating treatment caused small changes in the polyester fabrics’ tensile strength and air permeability.     

The combining process for bio-preparation of starch-sized cotton fabrics at high temperature

α-amylase and pectinase showed good compatibility. A desizing ratio of 95.4 %, a pectin removal rate of 80.4 % and a capillary effect height of 7.1 cm for cotton fabrics treated with α-amylase and pectinase were obtained by a one-bath for bio-desizing and bio-scouring process under the condition of 90 °C for 30 min. After the treatment of the nonionic surfactant Peregal O at 100 °C for 20 min, these important properties for the cotton fabrics were further improved to 98.7 %, 96.8 %, and 18.4 cm separately. The capillary effect height of desized cotton fabrics was improved from 0.2 cm to 6.4 cm by the removal of waxes because its hydrophobic nature of the cotton fabrics. The whole time for this new combining process with high temperature treatment was significantly shortened and it only took about 55 minutes.