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.     

Evaluation of aroma functionality imparted on natural indigo-dyed cotton fabrics

Long-term efficacy of aroma microcapsules on natural indigo-dyed cotton fabric was evaluated by objective and subjective tests. The fixation of aroma microcapsules was carried out by pad-dry-cure process on dyed cotton fabric. Mercerized cotton fabric was dyed with natural indigo obtained from Polygonum tintorium (via the modified Niram method) and subsequently padded with melamine-formaldehyde microcapsules containing aroma essential oil (natural source of a Chinese arborvitae 20-25 %). Softener was applied in the same (one-step) or sequential (two-step) padding bath. We confirmed that microcapsules were fixed on cotton fibers by SEM analysis. The addition of softener was not much effective for the fabric performances on softness or air permeability. All the colorfastness ratings were above 4/5 and the color difference was within the acceptable range of 1.62-2.08. The efficacy of fabric samples stored for 2 years was evaluated using the GC/MS-headspace technique and the samples stored for 0.5, 1.5, and 2.5 years were also evaluated in terms of aroma release by the human perception test. Bornyl acetate was confirmed as the main component of essential oil, which was continuously released by the microcapsule-treated fabric (D/MC) during storage for more than 2 years. In durability and human perception tests, the microcapsules on the cotton fabric were stable to laundering, rubbing, ironing, and light.     

Study on the aging and yellowing properties of sebum-soiled cotton fabrics

The accumulation and autoxidation of residual oily soil from human sebum is regarded as a major reason for the aging and yellowing of clothing and household textiles. In this study, the yellowing degree of cotton fabrics soiled with human sebum components and aged under various environmental conditions (various temperatures, humidities and light intensities etc.) were investigated. The representative sebum components including olive oil, squalene, oleic acid and cottonseed oil were selected and their chemical changes were studied by FTIR analysis. The results showed that, olive oil, squalene, oleic acid and cottonseed oil could caused more significant fabric-yellowing than other components in human sebum, and the yellowing degree could become higher with increasing temperatures, humidities and/or light intensities of aging environments. The chemical structures of olive oil, squalene and oleic acid changed remarkably after aging treatment. The aging products contained hydroxyl groups and carbonyl groups, and the conjugated C=O group was considered to be the chemical species leading to the yellowing of sebum-soiled fabrics.     

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.     

Effect of glycols and catalysts on cotton fabrics treated with glyoxal

The optimum conditions for durable press treatment of cotton fabrics using glyoxal as a nonformaldehyde crosslinking agent were investigated. Crosslinking reaction was conducted in the presence of different catalysts such as aluminum sulfate, magnesium chloride, or magnesium chloride-citric acid mixture at various mole ratios of catalyst to glyoxal. Aluminum sulfate was proven the most effective one among those used. Glycol addition into a glyoxal padding bath increased the wrinkle recovery angle(WRA) and whiteness of treated fabrics. The optimum mole ratio of glycol to glyoxal was 1:1. Diethylene glycol addition produced better overall performance to the glyoxal-crosslinked fabric compared to ethylene glycol addition.     

Nano-TiO<Subscript>2</Subscript> based multilayer film deposition on cotton fabrics for UV-protection

Nano-TiO₂ based multilayer nanocomposite films were fabricated on cationically modified woven cotton fabrics by layer-by-layer molecular self-assembly technique. Cationization process was used to obtain cationic surface charge on cotton fabrics. Attenuated total reflectance Fourier transform infrared spectroscopy analyses were used to verify the presence of cationic surface charge and multilayer films deposited on the fabrics. Scanning electron microscope micrographs of poly(sodium 4-styrene sulfonate)/TiO₂, nano polyurethane/TiO₂, and TiO₂/poly(diallyldimethylammonium chloride) multilayer films deposited on cotton fabrics were taken. With nano-TiO₂ based multilayer film deposition, the protection of cotton fabrics against UV radiation is enhanced. The UV protection durability of the self-assembled multilayer films deposited on the cotton fabrics was analyzed after 10 and 20 washing cycles at 40 °C for 30 min. Air permeability and whiteness value analysis were performed on the untreated and multilayer film deposited cotton fabrics. The effect of layer-by-layer deposition process on tensile strength properties of the warp and weft yarns was determined.     

Water repellent cotton fabrics prepared by PTFE RF sputtering

A poly(tetrafluoroethylene) (PTFE) sputtering technique was employed to introduce water repellency onto the surfaces of commercial cotton fabrics. Sputtering power, time, and argon pressure were varied as processing parameters, when PTFE coatings were applied on the fabrics. Total 27 different samples were prepared to compare their water repellent properties, which were investigated by contact angle measurements. Morphology of the PTFE coatings were probed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also, the extent of the coating was examined by X-ray photoelectron spectroscopy (XPS). Maximum hydrophobicity was obtained when PTFE coating was extensive enough to cover cotton fabrics almost completely, and the extensive coating was the roughest among the samples prepared in this study.     

Dyeing and DP treatment of sol-gel pre-treated cotton fabrics

Cotton samples were pre-treated with various sol solutions containing different alkoxysilanes (TEOS, GPTMS, APTES, and TESP-SA). The as-prepared cotton samples were dyed with 2 % owf Red and 4 % owf Blue. Furthermore, dyed cotton samples were after-treated with the alkoxysilanes. The alkoxysilane were also incorporated into the dyeing bath. The as- prepared cotton samples were subjected to a treatment with the non-formaldehyde durable press finishing agent BTCA in conjunction with the catalyst SHP. The textile materials were evaluated with respect to the colorimetric data (L*, a*, b*, ΔE*) and the color strength expressed in terms of K/S values. Tensile strength and dry crease recovery angles of the durable pressfinished samples were measured. The findings indicate that APTES and TESP-SA exert a significant influence on the color properties.     

Water repellent treatment of cotton fabrics by electron beam irradiation

In this study, traditional dip-pad-cure (DPC) process and electron beam (EB) irradiation were used to graft cotton fabrics with fluorine containing chemical, 1H,1H,2H,2H-perfluorooctyl acrylate (PFA). The grafted cotton fabrics were characterized by FT-IR and SEM. The water repellent properties were measured by contact angle, hydrostatic pressure, and spry test. It was found that there was no significant difference between the grafted cotton fabrics with DPC and EB methods, and the treated fabrics showed good water-resistant properties. The grafted cotton fabrics also showed good washing stability. By measuring the bending rigidity and bending hysteresis, it was found that the cotton fabrics grafted with PFA became softer than untreated samples.     

Electrically conductive and hydrophobic cotton fabrics by polypyrrole-oleic acid coating

Hydrophobic polypyrrole-coated fabrics with improved electrical conductivity were produced embedding oleic acid as counter-ion. Hydrophobisation of polypyrrole was carried out by means of an ion exchange process after deposition of polypyrrole on cotton fabrics. The fabrics coated with oleic acid-doped polypyrrole showed contact angle of 111°, drop absorption time of 7 minutes and high water repellence, while electrical conductivity increased of ～2 times and heat generation improved, too. Moreover, oleic acid demonstrated a great stability as counter-ion in polypyrrole matrix being present also after washing.