Finishing of cotton fabrics with poly (N-vinyl-2-pyrrolidone) to improve their performance and antibacterial properties

Cotton fabric was thermally crosslinked with poly (N-vinyl-2-pyrrolidone) (PVP) at different conditions including temperature, time, PVP concentrations and molecular weights. Results indicated that treating the cotton fabrics with 4% aqueous solution of PVP of molecular weight 10,000 Dalton followed by drying at 85 °C for 5 min then curing at 160 °C for 3 min results in crosslinking as will as an improvement in some performance properties of that fabrics such as resiliency, tensile strength, and acid dyeability. Post-treating PVP crosslinked fabric with 5% iodine in ethanol solution for 5 h at 50 °C imparts antibacterial activity against Staphylococcus aureus and Escherichia coli. Moreover, incorporation of PVP in the easy-care finishing of cotton fabrics, as polymer additive, with N,N-dimethylol 4,5-dihydroxyethylene urea as a crosslinker enhances some of the performance properties of finished fabrics such as the nitrogen content, tensile strength and acid dyeability along with decreasing resiliency as well as whiteness index, whereas the ester crosslinking with citric acid, in presence of PVP, enhances resilience, tensile strength and whiteness indices accompanied with a reduction in the %N of the treated fabrics. Infra red spectrum of PVP crosslinked fabric as well as EDX analysis of loaded iodine on PVP crosslinked cotton fabric were investigated.     

Utilization of acrylates emulsion terpolymer with chitosan as a finishing agent for cotton fabrics

Cotton fabrics were treated with finishing bath formulation containing emulsion lattices based on acrylate monomers, chitosan and polyethylene glycol (PEG) to provide cotton fabrics with antibacterial, UV-protection as well as improvement of dyeing properties with direct, acid and reactive dyes. The terpolymer emulsion, chitosan and PEG concentrations as well as fabric pretreatment with alkali significantly affected the performance properties, antimicrobial activity, UV-protection and dyeing behavior of treated cotton fabric. The finished fabrics were characterized in terms of FTIR, X-ray diffraction, scanning electron microscope (SEM) as well as mechanical properties such as tensile strength, elongation at break (%), abrasion resistance and air permeability. The obtained data showed that the tested fabrics have appropriate antibacterial activity with highly UV-protection properties with increasing chitosan concentration up to 3%. The mechanical properties expressed as tensile strength and abrasion resistance increased after finishing treatment. Moreover, the performance of the finished fabrics and dyeing properties with different dyes classes were greatly influenced by the action of alkali pretreatment of cotton fabrics, adding the polyethylene glycol to the finishing bath formulation as well as emulsion and chitosan concentrations.     

Antimicrobial and chemical detoxifying functions of cotton fabrics containing different benzophenone derivatives

Several benzophenone chromophoric groups were incorporated onto cotton fabrics by using 4-hydroxybenzophenone, 4,4′-dihydroxybenzophenone, 4-chloro-4′-hydroxybenzophenone, and 4-benzoylbenzoic acid as reagents. The fabric treatment was conducted by a pad-dry-cure method, and the benzophenone chromophoric group incorporated cotton fabrics were characterized and confirmed by FTIR. Tensile strengths of benzophenone chromophoric groups modified cotton fabrics were also measured. 4-Hydroxybenzophenone treated cotton fabric showed the most powerful antibacterial activity among all samples, and 4-benzoylbenzoic acid treated cotton fabric demonstrated pesticide degradation ability, under UV irradiation.     

Contamination of foods by food handlers: experiments on hepatitis A virus transfer to food and its interruption

Hepatitis A virus (HAV) is an important pathogen which has been responsible for many food-borne outbreaks. HAV-excreting food handlers, especially those with poor hygienic practices, can contaminate the foods which they handle. Consumption of such foods without further processing has been known to result in cases of infectious hepatitis. Since quantitative data on virus transfer during contact of hands with foods is not available, we investigated the transfer of HAV from artificially contaminated fingerpads of adult volunteers to pieces of fresh lettuce. Touching the lettuce with artificially contaminated fingerpads for 10 s at a pressure of 0.2 to 0.4 kg/cm(2) resulted in transfer of 9.2% +/- 0.9% of the infectious virus. The pretreatments tested to interrupt virus transfer from contaminated fingerpads included (i) hard-water rinsing and towel drying, (ii) application of a domestic or commercial topical agent followed by water rinsing and towel drying, and (iii) exposure to a hand gel containing 62% ethanol or 75% liquid ethanol without water rinsing or towel drying. When the fingerpads were treated with the topical agents or alcohol before the lettuce was touched, the amount of infectious virus transferred to lettuce was reduced from 9.2% to between 0.3 and 0.6% (depending on the topical agent used), which was a reduction in virus transfer of up to 30-fold. Surprisingly, no virus transfer to lettuce was detected when the fingerpads were rinsed with water alone before the lettuce was touched. However, additional experiments with water rinsing in which smaller volumes of water were used (1 ml instead of 15 ml) showed that the rate of virus transfer to lettuce was 0.3% +/- 0.1%. The variability in virus transfer rates following water rinsing may indicate that the volume of water at least in part influences virus removal from the fingerpads differently, a possibility which should be investigated further. This study provided novel information concerning the rate of virus transfer to foods and a model for investigating the transfer of viral and other food-borne pathogens from contaminated hands to foods, as well as techniques for interrupting such transfer to improve food safety.     

Enhancing antimicrobial properties of dyed and finished cotton fabrics

1,2,3-Benzothiazole-7-thiocarboxylic acid-S-methylester (commercially known as Actigard^® AM-87) was utilized to impart cotton fabric durable antimicrobial properties. Finishing treatment was carried out under a variety of conditions. The latter were included, effect of pH, concentration of antibacterial agents, curing temperature and curing time. The effect of fabric construction, mercerization, and dyeing with different dyestuff were also investigated. The study was also extended to investigate the technical feasibility of combining antimicrobial finishing treatment in question with other finishing treatment generally carried out on cotton fabric, like soft finishing and crease recovery finishing. The treated fabrics were monitored for antimicrobial properties before and after washing. The treated fabrics were also evaluated for the physio-mechanical properties like fabric tensile strength, elongation at break (or bursting strength for knitted fabric), wettability, crease recovery angle, whiteness index and roughness. Results obtained show that, the most appropriate conditions for treatment cotton fabric with Actigard^® are: padding the cotton fabric in aqueous solution containing 6% Actigard^® at pH 5 (adjusted using formic acid) then squeezed to wet pick up of 100%, dried at 80 °C for 5 min then cured at 100 °C for 150 s. The untreated cotton fabric did not show any antimicrobial activity towards Staphylococcus aureus or Escherichia coli. Treatment of cotton fabric with Actigard^® improves its antimicrobial properties towards S. aureus or E. coli. It is also observed that, treatment of cotton fabric with Actigard^® marginally decreases fabric tensile strength, elongation at break, roughness and WI, whereas; both wettability and crease recovery angle remain practically intact. This was observed whether the fabric was pre-mercerized or not.     

Factors Affecting the Persistence of Staphylococcus aureus on Fabrics

The persistence of Staphylococcus aureus (Smith) on wool blanket, wool gabardine, cotton sheeting, cotton knit jersey, cotton terry cloth, and cotton wash-and-wear fabrics was studied. The fabrics were exposed to bacterial populations by three methods: direct contact, aerosol, and a lyophilized mixture of bacteria and dust having a high content of textile fibers. The contaminated fabrics were held in 35 or 78% relative humidities at 25 C. In general, the persistence time of S. aureus populations on fabrics held in 35% relative humidity was substantially longer when the fabrics were contaminated by exposure to aerosolized cultures or to dust containing bacteria than when contaminated by direct contact. In a 78% relative humidity, bacterial populations on the fabrics persisted for substantially shorter periods of time regardless of the mode of contamination or fabric type. Cotton wash-and-wear fabric (treated with a modified triazone resin) was the material on which populations of S. aureus persisted for the shortest time. This organism retained its virulence for Swiss mice after being recovered from wool gabardine swatches held 4 weeks in 35% relative humidity and 6 weeks in 78% relative humidity.     

Incorporation of chlorohexidin diacetate into cotton fabrics grafted with glycidyl methacrylate and cyclodextrin

Linear electron beam radiation was used to induce grafting of glycidyl methacrylate/β-cyclodextrin mixture onto cotton fabric. Chlorohexidin diacetate was incorporated to the cavities of cyclodextrin fixed on the cotton fabric to form an inclusion complex having antimicrobial activity. After incorporating chlorohexidin diacetate, the fabric was subjected to several washing cycles to examine the durability of the antimicrobial finishing. Control and grafted cotton fabrics (before and after loading with antimicrobial agent) were characterized for their antimicrobial activity against different kinds of bacteria and fungi.Grafted fabrics loaded with antimicrobial agent were found to show good antimicrobial activity in comparison with control and grafted fabrics which are not loaded with antimicrobial agent. The grafted fabrics loaded with antimicrobial agent were found also to exhibit good antimicrobial activity after five washings and this lasting antimicrobial activity can be attributed to the inclusion complex formed between chlorohexidin diacetate molecules and the cavities of cyclodextrin.     

Effect of hygroscopic fabrics on wear comfort in the fluctuating microclimate of clothing

1. 1. A new type of simulator for clothing microclimate was designed and constructed.

2. 2. The simulator was designed to simulate the humidity fluctuation of clothing microclimate as observed under light working conditions and to measure the surface temperature of sample fabrics against the skin by means of a radiation thermometer.

3. 3. Knitted fabrics of cotton and polyester, and polyethylene films were used as specimens with different hygroscopicities.

4. 4. The quick rise and fall in the surface temperature of cotton fabric was observed under rapid fluctuations of the microclimate humidity.

5. 5. Under the same humidity fluctuations, the temperature of polyester fabric rose and fell more moderately than that of cotton fabrics, and the temperature of the polyethylene film did not change. When the rate of change in stimulus temperature is higher, the threshold temperature of warm sensation of the skin comes closer to a given adaption temperature.

6. 6. Therefore, the rapid and large changes in the fabric temperature against the skin, which were observed especially for hygroscopic cotton fabric, must affect the thermal comfort of clothing.

Effect of post- and pre-crosslinking of cotton fabrics on the efficiency of biofinishing with cellulase enzyme

Four different types of cotton-based fabrics, namely, loom-state cotton, cotton/polyester (50/50), cotton/polyester (35/65) and grey mercerized fabrics were bioscoured and bleached. The four substrates are given enzymatic treatment using cellulase enzyme to affect bio-polishing followed by crosslinking using N,N-dimethylol 4,5-dihydroxyethylene urea (DMDHEU) to affect easy care finishing. In another series of experiments the said bioscoured–bleached substrates were similarly crosslinked followed by bio-polishing. Technical properties of the treated fabric that were monitored include: nitrogen content, loss in fabric weight, tensile strength, elongation at break, tear strength, whiteness index, surface roughness and wrinkle recovery angle. Scanning electron micrograph was also examined. Conclusions arrived at from these studies indicated that: post-crosslinking and pre-crosslinking revealed marginal differences in N%, wrinkle recovery angle and whiteness index, a point which validates the argument that cellulase enzyme could not break down the DMDHEU crosslinks within the molecular structure of cotton-containing fabrics. Meanwhile the surface roughness obtained with pre-crosslinking is a bit higher than those of post-crosslinking. Moreover, post-crosslinking caused higher losses in strength properties than pre-crosslinking. Scanning electron micrograph shows that cotton sample pre-crosslinked is almost smooth than those post-crosslinked.     

Adherence of bacterial spores to encrusted fabrics

Adherence of Bacillus megaterium spores to fabrics depends on fabric composition and texture. Adherence to cotton terry cloth is higher than to plain cotton and cotton-polyester fabrics. The adherence is always proportionally enhanced by the presence of organic and inorganic encrustation on the surface of fibres. These encrustations are deposited when fabrics are washed without adequate detergents. This frequently happens because of attempts to limit or banish the use of efficient ingredients (such as sodium tripolyphosphate) for ecological reasons and to use low temperature washing methods to permit energy savings. Encrustation, inadequate detergency and low temperature washing can concur to sustain a high level of bacterial contamination on the fabric surface.     

Quantification of bacterial adherence on different textile fabrics

This research studied the adherent behaviour of gram-negative Escherichia coli on different weft knitted textile fabrics made of cotton, polyester filaments and polyester (staple)-cotton blended yarn. We compared the bacterial adherence of 18-h-old E. coli cells on all the three types of fabrics under the same experimental conditions. The maximum adherence was found in cotton, followed by the polyester blend; the least adherence was in polyester fabrics. Scanning electron micrographs showed that surface morphology of fabrics also plays an important role during adherence. Cotton fabric, with a rough surface, attracted more bacterial cells compared to the smooth polyester surface. Comparing the FTIR spectra of different fabrics and E. coli it was found that both cotton and E. coli have abundant free hydroxyl groups that may interact strongly with each other and with other hydrophilic groups such as carboxyl, phosphate, and amides. This may be one of the reasons for the greater adherence on cotton as compared to hydrophobic polyester fabric. Finally, the effect of bacterial adherence on loss of strength in different fabrics was analysed. It was found that the maximum decrease in strength occurred in cotton fabrics and the least in polyester fabrics. The present study suggests a procedure for quantifying bacterial adherence on different textile fabrics. This technique can be used with different bacterial strains and varieties of fabrics for quantifying the adherent bacterial cells, and would be of great use in developing and comparing different antimicrobial finished products of the textile industry.     

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

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

Microwave curing for producing cotton fabrics with easy care and antibacterial properties

A new microwave curing system was used to affect crosslinking of cotton fabric with nonformaldehyde finishes, namely, glyoxal, glutaraldehyde and 1,2,3,4 butanetetracarboxylic acid (BTCA). Water soluble chitosan was incorporated in the finishing bath in order to impart antibacterial activity to the fabric in addition to the ease of care characteristics. Glyoxal proved to be the best finish and, hence, it was studied along with the chitosan under a variety of conditions including chitosan concentrations, power and time of microwave curing. Besides the crease recovery and strength properties of the finished fabrics, the latter were also monitored for N%, antibacterial activity and characterized using scanning electron microscope (SEM) and FTIR spectra when compared. With conventional curing system, the microwave curing system was found advantageous in production of cotton fabrics with easy care antibacterial properties without high losses in strength properties.     

A quantitative study of the survival of two species of Candida on porous and non-porous environmental surfaces and hands

AIMS: In spite of the importance of many species of Candida as human pathogens, little is known about their ability to survive on animate and inanimate surfaces. Such information is essential in understanding the vehicles and modes of their spread, and in designing proper infection control strategies against them. The aim of this study was to generate comparative quantitative data in this regard. METHODS AND RESULTS: The survival of one clinical isolate each of Candida albicans and C. parapsilosis on two types of hard inanimate surfaces (glass and stainless steel) and two types of fabrics (100% cotton and a blend of 50% cotton and 50% polyester) was evaluated under ambient conditions (air temperature 22 +/- 2 degrees C; relative humidity 45-62%) using quantitative test protocols. The survival of C. albicans was also assessed on human skin, using the fingerpads of adult volunteers as carriers. Each carrier surface received 10 microl of the test suspension containing a soil load to simulate body fluids. When dried on glass and stainless steel carriers, C. albicans and C. parapsilosis remained viable for at least three and 14 days, respectively. Both species could survive for at least 14 days on both types of fabric. On the skin, 20% of the viable C. albicans remained detectable one hour post-inoculation. SIGNIFICANCE AND IMPACT OF THE STUDY: This quantitative and comparative study demonstrated the potential for, and differences in the ability of clinically significant species of Candida to remain viable on porous and non-porous inanimate surfaces as well as on human hands. These results should help in understanding the epidemiology of nosocomial infections due to Candida, and in designing better prevention and control strategies against them.     

Application of Thermostable Xylanase of Bacillus pumilus in Textile Processing

Desizing of cotton and micropoly fabrics was done using thermostable xylanase from Bacillus pumilus ASH. Micropoly fabric showed better desizing than cotton under same conditions. Violet scale readings from the TEGEWA test after enzymatic desizing for 90 min at pH 7.0 and at 60°C showed the readings falling in the range of 4–5, indicating good desizing efficiency. During bioscouring the weight loss values and liberation of reducing sugars were highest when EDTA was used along with xylanase. The weight loss value of 1.5% was observed for dry cotton fabric after 1 h in case of agitated system at pH 7.0 and at an optimal enzyme dosage of 5 IU/g. The weight loss values and the liberation of reducing sugars were higher in case of cotton fabrics. Wetting time of fabrics was lowered significantly after 60 min of bioscouring using xylanase. Increase in temperature or concentration of surfactant led to further reduction in the wetting time. The whiteness values of fabrics after bioscouring were 0.9% higher than the chemically scoured fabrics indicating good efficacy of xylanase during the scouring process.     

New development for combined bioscouring and bleaching of cotton-based fabrics

A thorough investigation into conditions appropriate for effecting combined eco-friendly bioscouring and/or bleaching of cotton-based fabrics was undertaken. Fabrics used include cotton, grey mercerized cotton, cotton/polyester blend 50/50 and cotton/polyester blend 35/65. The four cotton-based fabric were subjected to bioscouring by single use of alkaline pectinase enzymes or by using binary mixtures of alkaline pectinase and cellulase enzymes under a variety of conditions. Results of bioscouring show that, the bioscoured substrates exhibit fabrics performances which are comparable with these of the conventional alkali scouring. It has been also found that, incorporation of ethylenediaminetetraacetic acid (EDTA) in the bioscouring with mixture from alkaline pectinase and cellulase improves the performance of the bioscoured fabrics. Addition of β-cyclodextrin to the bioscouring solution using alkaline pectinase in admixtures with cellulase acts in favor of technical properties and performance of the bioscoured fabrics. Concurrent bioscouring and bleaching by in situ formed peracetic acid using tetraacetylethylenediamine (TAED) and H₂O₂ was also investigated. The results reveal unequivocally that the environmentally sound technology brought about by current development is by far the best. The new development involves a single-stage process for full purification/preparation of cotton textiles. The new development at its optimal comprises treatment of the fabric with an aqueous formulation consisting of alkaline pectinase enzyme (2 g/L), TAED (15 g/L), H₂O₂ (5 g/L), nonionic wetting agent (0.5 g/L) and sodium silicate (2 g/L). The treatment is carried out at 60 °C for 60 min. Beside the advantages of the new development with respect to major technical fabric properties, it is eco-friendly and reproducible. This advocates the new development for mill trials.     

The influence of silver content on antimicrobial activity and color of cotton fabrics functionalized with Ag nanoparticles

The aim of this study was to examine the antimicrobial efficiency and color changes of cotton fabrics loaded with colloidal silver nanoparticles which were synthesized without using any stabilizer. The influence of colloidal concentration and consequently, the amount of silver deposited onto the fabric surface, on antimicrobial activity against Gram-negative bacterium Escherichia coli, Gram-positive bacterium Staphylococcus aureus and fungus Candida albicans as well as laundering durability of obtained effects were studied. Although cotton fabrics loaded with silver nanoparticles from 10 ppm colloid exhibited good antimicrobial efficiency, their poor laundering durability indicated that higher concentrated colloids (50 ppm) must be applied for obtaining long-term durability. Additionally, the influence of dyeing with C.I. Direct Red 81 on antimicrobial activity of cotton fabrics loaded with silver nanoparticles as well as the influence of their presence on the color change of dyed fabrics were evaluated. Unlike color change, the antimicrobial efficiency was not affected by the order of dyeing and loading of silver nanoparticles.     

Quantitative Studies on Fabrics as Disseminators of Viruses: II. Persistence of Poliomyelitis Virus on Cotton and Wool Fabrics

The length of time that poliovirus could be recovered from wool gabardine and blanket, and from cotton sheeting, terry cloth, and knit jersey fabrics was determined under conditions of controlled temperature and humidity (25 C in 35 and 78% relative humidities). Three types of exposure of the fabrics to viruses were used: direct contact, aerosol, and virus-containing household dust having a high content of textile fibers. When held in 35% relative humidity, virus persisted for 20 weeks on wool fabrics, but only 1 to 4 weeks on cotton fabrics. At this relative humidity, virus titers on wool fabrics decreased rapidly to low but detectable levels which persisted for long periods of time, whereas in 78% relative humidity the decrease in virus titer was less rapid, but the period of viral persistence was shorter. Generally, virus titers on cotton fabrics held in both relative humidities decreased exponentially to an undetectable level. The method of exposure to virus had a definite effect on the duration of viral persistence on a given fabric. Virus contained in household dust was least stable.     

Coloured and low conductive fabrics by in situ laccase-catalysed polymerization

Coloured and conductive fabrics were obtained through “in situ” laccase polymerization of catechol and p-phenylenediamine under high-pressure homogenization. Both monomers, catechol and p-phenylenediamine, were polymerized by different laccase forms, namely native, PEGylated and Epoxy-PEGylated. All the catalysts were placed inside a textile fabric bag which served simultaneously as enzyme support and as substrate for coating with the newly produced polymers. The PEGylated laccase forms gave rise to a higher amount of oligomers/polymers and higher colouration level of polyethylene terephthalate (PET), cotton and wool fabrics compared to native laccase. Both functional polymers were able to confer conductivity to the substrates however in a different extent. Fabrics coated with poly(p-phenylenediamine) present higher conductivity, rather due to its polymerized structure than to the amount of polymer produced by enzyme catalysis. Herein a green approach was presented to produce polyphenols with increased fixation onto different textile substrates. These substrates reach high levels of colouration and good fastness behaviour after washing.     

An approach for vat color printing on cotton and polyester fabrics with electron beam irradiation curable formulations

Accelerated electrons delivered by electron beam accelerator were used to fix vat colors, incorporated in curable formulations containing diluting monomer and an oligomer, to cellulosic fabric, cotton and polyester fabric. Tetrahydrofurfuryl acrylate, hexane dioldiacrylate, monomers and trifunctional urethane methacrylate, oligomer were used as curable base beside ethylene glycol. The fabrics were printed with these formulations and exposed to various doses of electron beam irradiation generated from the 1.5 MeV (25 kW) electron beam accelerator machine. Critical factors included the irradiation dose, formulation composition, and vat color concentration were studied. The fabrics printed with the vat colors by electron beam irradiation displayed higher color yield than those fabrics printed by the conventional curing at equal vat color ratios. The durable properties of fabrics printed by electron beam irradiation except the roughness properties are extremely better than those printed by conventional fixation method.