Use of lipoprotein lipase in the improvement of some properties of wool fabrics

Wool fabrics were pretreated with hydrogen peroxide in the presence of different stabilisers; namely, sodium silicate, magnesium sulphate and imino disuccinic acid sodium salt. The effect of stabiliser type and concentration on the properties of the treated wool were studied. Imino disuccinic acid sodium salt was found to be the most effective stabiliser for hydrogen peroxide when added to the bleaching bath of wool fabric. The effect of after‐treatment of the pre‐oxidised wool fabric with commercially produced lipoprotein lipase enzyme on its dyeability with acid and reactive dyes, as well as on some of its physico‐mechanical properties, was assessed. Chemical and microscopic analyses were conducted to assess changes in the chemical composition of wool treated with this system. Wool fabrics treated with hydrogen peroxide/imino disuccinic acid sodium salt/lipoprotein lipase enzyme exhibit improved wettability and, hence, dyeability with both acid and reactive dyes, as well as enhanced resistance to felting shrinkage and pilling, without severe deterioration in the fabric’s inherent properties.     

Improving the Adhesive Property of Polyester Fabric with Sodium Hydroxide and Corona Discharge Treatment

In this study, polyester fabric was treated with sodium hydroxide combined with corona discharge to modify the surface properties. This was done to improve its adhesive property to ensure effective sizing with starch under different conditions. Scanning electron microscopy photographs showed that the surface of polyester fiber was etched more by the combined process than that by either corona discharge treatment or sodium hydroxide treatment. The results showed that the adhesive property of polyester fabric with starch was improved as a result of the treatment with sodium hydroxide or by corona discharge. However, fabric treated by the combined methods showed even better results. This study shows great potential for applying corona discharge in the sizing process of polyester staple yarn.     

Transglutaminase‐mediated crosslinking of gelatin onto wool surfaces to improve the fabric properties

In this study, transglutaminase (TGase)‐mediated crosslinking of gelatin on the surface of wool and its effect on the properties of wool fabric were investigated. For the wool fabric used in this study, gelatin (3 g/L) treatment for 1 h combined with 20 U/g of fabric microbial TGase reduced the area shrinkage of KMnO₄‐pretreated wool fabric from 6.53 ± 0.06 to 1.92 ± 0.15%, which was more effective than that treated with gelatin alone (in which the area shrinkage was reduced to 4.02 ± 0.10%). At the same time, the tensile strength recovered from 267 ± 2.0 to 335 ± 2.1 N. The antifelting ability of treated wool fabric exhibited better washing durability. Scanning electron micrographs showed that the gelatin material smoothed the wool fiber surface by coating or filling the raised scales of the wool with TGase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Calendar of events

The influence of the gas type, air or nitrogen, and the treatment time in an RF glow discharge treatment on the shrink resistance properties of knitted wool fabric and wetting properties of keratin fibres were studied. Wetting properties were determined by means of contact angle measurements on single keratin fibres. This method allows measuring accurately the influence of the plasma gas type and treatment time on fibre hydrophilicity, and its modification with the time elapsed after plasma treatment. The modification of the surface properties should be taken into account, especially, when a biopolymer after-treatment is applied to achieve wool shrink resistance. Surface chemical changes were studied by means of XPS. Topographical changes in the wool fibre surface were observed by scanning electron microscopy (SEM) and surface damage was evaluated by means of the Herbig sac formation. Both air and nitrogen plasma treatments impart shrink resistance to wool fabric and hydrophilic properties to the keratin fibres. Even short exposure times are found to be enough to decrease drastically the advancing water contact angle and, therefore, to increase the shrink resistance effect. Slight differences were observed between the air and nitrogen plasma treatments. The time elapsed after the plasma treatment promotes an increase of the advancing contact angle and a decrease of chitosan adsorption. The plasma treatments studied here modify chemically the epicuticle but it is not removed.     

Fluorination-a novel pretreatment for wool to impart shrink resistance

The use of gaseous fluorination as a pretreatment for wool has been assessed and compared with corona discharge. Mechanical and shrinkage properties have been examined both before and after the application of two commercial shrinkproofing polymers. Fluorination reduces fabric shrinkage during washing, and the subsequent application of low levels of Basolan MW imparts machine washability with no impairment of fabric handle.     

Surface modification of wool fabric for printing with acid and reactive dyes

The present study investigates environmentally safe pretreatments for wool fabric to improve its printing with acid and reactive dyes. Wool fabric was pretreated either with activated hydrogen peroxide using tetraacetylethylenediamine or with lipase enzyme under specified conditions. Some acid and reactive dyes were applied for wool printing using normal techniques. These treatments were found to improve the colour intensity of the printed fabrics to a level comparable with those of prechlorinated wool fabrics.     

Combined effect of corona discharge and enzymatic treatment on the mechanical and surface properties of wool

The enzymatic treatment of textile fibers is a nontoxic and environmentally benign process. The objective of the present study is to investigate the improvement of physic-chemical characteristics of wool fabrics by surface modification induced by corona discharge and enzymatic treatment with protease and cellulose. Thus, it was found that, compared with pristine wool fabric, the enzyme-treated fabrics exhibited lower tensile strength, increased elongation, and higher alkali solubility. The surface roughness and the zeta potential of the enzyme-treated wool fabrics decreased with increasing treatment duration.     

Surface modification of textiles by glow discharge technique: Part II: Low frequency plasma treatment of wool fabrics with acrylic acid

In this study, wool fibers are modified by low frequency plasma polymerization of acrylic acid regarding to its' hydrophobic character due to cuticular cells at their surfaces. Variables of the plasma glow discharge processes were power (40–100 W) and exposure time (5–45 min). The effect of plasma modification in the performance properties of wool were investigated on the basis of hydrophilicity of wool, average wrinkle recovery angle, and breaking strength. The surface chemical structures of fabrics were examined with x‐ray photoelectron spectroscopy. The hydrophobic wool fabric became hydrophilic after all plasma treatments except one (40W–5 min). Average wrinkle recovery angle of the treated fabrics were between 157 and 178°, while that of untreated fabric was 180°. The treated fabrics had a little bit lower angles according to the untreated fabric. However, even the lowest value as 157° means that the fabric has a good crease resistance property. The breaking strengths of fabrics were increased up to 26% after the plasma treatments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The use of ultraviolet radiation in an adsorbable organohalogen-free print preparation for wool and in wool dyeing: the Siroflash process

German legislation controlling the discharge of adsorbable organohalogens (AOX) in process effluents has focused attention on the need for environmentally acceptable alternatives to chlorination as a prepare-for-print (PFP) treatment for wool. The Siroflash process is a novel AOX-free approach which involves continuous UV irradiation of dry wool fabric, followed by conventional wet oxidation using hydrogen peroxide or permonosulphuric acid. Although permonosulphuric acid or peroxide treatments alone are ineffective as a PFP, the colour yields of prints on Siroflash-treated fabric are similar to those on chlorinated wool. The synergistic interaction between UV exposure and wet oxidation results in high levels of cystine oxidation, cuticle damage and loss of soluble protein, all of which are highly specific to irradiated surface fibres. UV irradiation of wool can significantly increase dyeing colour yields. The use of 1:1 metal-complex dyes is particularly effective, and a 3% o. w. f. dyeing on UV-treated fabric can produce a better depth of shade than a 5% dyeing on untreated fabric.     

Research in the cold pad–batch dyeing process for wool pretreated by hydrogen peroxide

The cold pad–batch dyeing process of wool pretreated by hydrogen peroxide was carried out with Lanasol reactive dyes and Realan reactive dyes. The influences of various conditions of the dyeing process, including urea dosage, sodium bisulphite dosage, pH value, batching time and the liquor pickup on colour yield, were analysed. Fixation, levelness of dyeing, dye penetration, colour fastness, breaking strength and elongation were compared between untreated and treated wool fabrics. The study showed that cold pad–batch dyeing of wool fabric is a good prospect for future use because of the resulting advantages, such as higher fixation yield, less energy usage and lower sewage discharge.     

Low‐temperature plasma processing for the enhancement of surface properties and dyeability of wool fabric

In the present investigation, wool fabric was treated with a low‐temperature air plasma. The plasma discharge power and treatment time were varied. The effect of plasma treatment on various fabric properties such as wettability, wickability, dyeability, crease recovery angle, breaking strength, and elongation at break was investigated. Surface morphology was studied using SEM micrographs. The fabric became substantially hydrophilic even with a short duration of air plasma treatment of 30 s with improvement in dye uptake and in the rate of dyeing when dyed at a lower temperature. Under these treatment conditions, aging was almost nil in a dry environment, even after 45 days, whereas some aging was observed in a humid (75% relative humidity) environment. A 20% increase in the breaking strength and 24% increase in the elongation at break were observed with reduction in wrinkle recovery angle to 133–144° from 169° for untreated fabric. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43097.     

The effect of various anti-setting systems in wool dyeing. Part 1: Hydrogen peroxide based systems

Extensive setting of wool fabrics occurs during piece dyeing at the boil and gives rise to adverse changes in dimensional stability such as variable hygral expansion, loss in tensile strength and the appearance of unsightly marks such as 'crow's-feet' on the fabric surface. Anti-setting agents such as stabilised hydrogen peroxide systems have thus been marketed to control this problem. Much has been published regarding the anti-setting and hygral expansion properties achievable but little information regarding the chemical effect of boiling wool with acidic solutions of hydrogen peroxide is available. Fourier transform infrared reflectance spectroscopy has thus been extensively used to quantify the chemical changes occurring on boiling wool in such aqueous solutions of hydrogen peroxide.     

Corona-induced autohesion of polyethylene: Dependence of bonding on frequency and power consumption in various gases

The autohesion of polyethylene sheets was markedly improved by corona discharge treatments in oxygen, nitrogen, argon and helium. Equal bond strength was produced by an equal number of discharge cycles regardless of the time or frequency of application. At a given operating voltage the power consumed in a discharge rather than the chemical nature of a gas proved to be a factor controlling the enhancement of autohesion. The detrimental effect of the oxidation upon autohesion was noted after a prolonged treatment in an oxygen corona.     

Influence of low‐temperature plasma conditions on wicking properties of PA/PU knitted fabric

Plasma surface treatment has been extensively applied in the textile industry for the modification of polymer materials. In this study low‐temperature plasma (LTP) is used for surface treatment of polyamide/polyurethane (PA/PU) knitted fabric. The envisaged plasma effect is an increase in the surface energy of the treated textile, leading toward improved hydrophilic properties. The knitted fabric was treated by LTP using three non polymerizing gases: oxygen, air, and carbon dioxide. After plasma treatment, wettability of samples was tested through their wicking properties measuring capillary rise after water bath contact. The PA/PU knitted fabric samples treated with different plasma gases exhibited different hydrophilic performances. The influence of plasma variables (discharge power, time, pressure) was investigated. Although the chemical characteristics of elastan (PU) and nylon (PA) threads are different, the study has demonstrated that plasma treatment can in the same time alter the surface‐wetting behavior of both the components of the knitted fabric. It was also shown how these treatments can be regulated to produce the desired level of hydrophilicity dependently on the request application. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Study on wettability improvement and its uniformity of wool fabric treated by atmospheric pressure plasma jet

The influence of processing parameters on wettability improvement and its uniformity of wool fabric treated by atmospheric pressure plasma jet (APPJ) was explored. A woven wool fabric was treated by APPJ under various treatment conditions such as different treatment time, different oxygen flow rate, and different jet‐to‐substrate distance. The water absorption time of wool fabric was measured to determine wettability improvement. The diffusion photo of water droplet on wool fabric surface was taken by digital camera to reflect wettability uniformity. After APPJ treatment, SEM observation showed that the scales on the wool fiber surface directly facing plasma jet pores were destroyed than those on the other fiber surface. XPS analysis showed that the carbon concentration substantially decreased. The concentration of oxygen and nitrogen significantly increased and but the concentration of sulfur and silicon did not obviously changed. With the addition of oxygen gas, more polar groups such as hydroxyl and carboxyl produced on wool fiber surface. The water absorption time of wool fabric greatly reduced indicating wettability improvement. The diffusion of water droplet on wool fabric surface was also larger and more homogenous suggesting uniform plasma treatment. It was concluded that the wettability improvement and its uniformity of the treated wool fabric increased and then decreased with the increasing oxygen flow rate and jet‐to‐substrate distance, and increased with the increasing treatment time. Therefore to achieve reasonable wettability and its uniformity of the wool fabric treated by APPJ, plasma treatment conditions have to be carefully chosen. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of atmospheric pressure helium plasma on felting and low temperature dyeing of wool

Wool fabrics were treated with atmospheric pressure helium glow discharge plasma in an attempt to improve felting and dyeing behavior with cold brand reactive dyes using cold pad‐batch method at neutral pH. On glow plasma treatment, the hydrophilicity of wool surface and its resistance toward felting was greatly improved without any significant damage to the cuticle layer. The color strength of the plasma treated dyed wool on the surface (in terms of K/S) was found to be nearly double of the color strength of dyed untreated wool fabric. However, the corresponding total dye uptake of the treated wool increased by a much lower value of 40%–50%. The reason behind this altered dyeing behavior was investigated by studying the dye kinetics using infinite bath and surface characteristics using SEM and SIMS. It was found that the glow plasma treatment greatly transformed the chemical surface of the wool fibers. It resulted in uniform removal of hydrophobic cuticular layer, which resulted in better diffusion of the dye molecules into the fiber, and formation of hydrophilic ? NH₂ groups near the surface, which helped in anchoring the dye molecules close to the surface giving higher color strength than expected. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Surface modification of synthetic fiber nonwoven fabrics with poly(acrylic acid) chains prepared by corona discharge induced grafting

The surface modification of synthetic fiber fabrics via corona discharge treatment and subsequent graft polymerization was investigated. Polyethylene (PE) nonwoven fabric and polyamide-6 (PA-6) nonwoven fabric were used as base fabrics. Acrylic acid (AAc) was graft polymerized onto the fabrics via corona discharge pre-treatment. The grafted amounts of PAAc were dependent on the grafting time, that of PA-6 being higher than that of PE. It was confirmed that the surface of the fibers constructing the fabric was fully covered with PAAc after the 20 min reaction. The surface of the PAAc grafted fabrics was characterized by X-ray photoelectron spectroscopy. The leakage of electrostatic charge from the fabric was determined and the dyeability was studied with methylene blue. The period of time in which the charge potential attenuated to 1/2 of the initial potential decreased drastically by grafting with PAAc. The grafted amount was enough for dyeing the entire fabrics.     

The effect of corona treatments on the hygral expansion of wool worsted fabrics

The effect of dry corona and aqueous treatments on the hygral expansion of wool gabardine has been investigated. Increasing the severity of the corona treatment produced a concomitant reduction in the hygral expansion of the fabric. X-ray photoelectron spectroscopy has been used to study the chemical modification of the wool fibre surface.     

Tracking the hydrophobicity recovery of PDMS compounds using the adhesive force determined by AFM force distance measurements

Polydimethylsiloxane (PDMS) materials show the unique phenomenon that when exposed to electrical discharge, such as corona discharge, their hydrophobic surface becomes hydrophilic. However, after a certain relaxation time they gradually regain their hydrophobicity. In this study the adhesive force obtained by AFM force distance measurements using a hydrophilic Si₃N₄ probe is used to track the recovery of the hydrophobicity. The time constant of the recovery can be determined by measuring the adhesive force as a function of the recovery time after corona exposure. It is shown how these time constants can be used to monitor the recovery rate as a function of corona treatment time for both filled and unfilled PDMS compounds.     

Application of enzymes and chitosan biopolymer to the antifelting finishing process

We surveyed environmentally friendly chemicals and mild processes that could be used to avoid the high absorbable organic halogen compounds (AOX) load and damage to the environment from the waste of wool plants. In this research, we sought to achieve a new zero‐AOX processing alternative to conventional processes such as chlorine/Hercosett processing and thus use environmentally friendly enzymes and chitosan as a biopolymer. We studied enzymatic, oxidative, and additive processes and various combinations of them to improve the shrink‐proofing and antifelting properties of wool. We performed our experiments with enzymatic treatments using commercial protease preparations, such as Perizym AFW, Alcalase 2.5L, Savinase 16L, and papain. The oxidative agents were hydrogen peroxide and sodium hypochloride, and the additive agents were based on polyurethane, polysiloxane, and silicone, as well as chitosan, a hydrophilic and natural polymer. We attempted to determine the agent or combination that best improved the shrink‐proofing properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2903–2908, 2004