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.     

Layer by layer assembly of nanosilver for high performance cotton fabrics

High performance cellulosic fabrics are of increasing attention as a wearable fabric with special functions. The current report deals with preparation of multifunctional cotton fabrics by using simple and facile layer by layer technique. Firstly, silver nitrate was reacted with carboxymethyl cellulose to prepare Ag nanoparticles-carboxymethyl cellulose composite. Multi-layers of the so-obtained composite were applied on the cotton fabrics using pad-dry-cure method. Ag nanoparticles were deposited with mean size of 18.2 nm onto cotton fabrics which served as a cross linker between carboxymethyl cellulose macromolecules and cotton macromolecular blocks. Application of composite multilayers brought new properties for the finished cloths such like coloration, ultraviolet resistance, electrical resistance and biocidal action. The ultraviolet transmission radiation was significantly reduced to 7-10 % after applying ten composite layers. Valuable antibacterial textiles which are required in different medical purposes could be successfully produced, as excellent antibacterial activities were achieved by using the reported method. The developed process can be easily adapted to the existing textile machinery, making it industrially viable to produce fabric’s versatility.     

Studies on electro-conductive fabrics prepared by in situ chemical polymerization of mixtures of pyrrole and thiophene onto polyester

This article reports on development, characterization, and performance of electro-conductive textiles prepared by in-situ chemical polymerization of mixtures of pyrrole and thiophene onto a polyester fabric. It was observed that a mixture of pyrrole and thiophene at 4:1 molar ratio resulted in the lowest surface resistivity among all the mixtures and the individual monomers studied. This electro-conductive fabric exhibited exponential voltage-current relationship. Further, it showed substantial fall in surface resistivity under the exposure of ultra-violet radiation. Under the application of DC voltage across it, an exponential rise in surface temperature was observed and the coefficient of rise in temperature was found to be directly related to the duration of voltage applied. Further, when subjected to mechanical straining, it displayed a decrease in resistivity followed by an increase of resistivity.     

Properties of anti-UV-finished cotton fabrics cured by blue light irradiation

To decrease the pollution discharge and energy consumption resulting from textile finishing using the conventional pad-dry-cure process, a blue light-curable digital finishing for textile was innovatively proposed. Based on the mechanism of blue light curing technique, a combination of the blue light curing process and anti-UV finishing was established in this study. A blue light-curable anti-UV finishing solution containing oligomers, monomers, photoinitiators, and anti-UV agents was padded onto the surface of the cotton fabrics, and then cured to form a tough film under blue light irradiation. The ultraviolet protection factor (UPF) value of the finished cotton fabrics was 50, the top level of international standards, demonstrating excellent UV resistance. The finished cotton fabrics also showed good rubbing and washing durability, and acceptable handle. The integration of an anti-UV finishing with the blue light curing technique presents some unique advantages in terms of environmental protection and application potential.     

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.     

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.     

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.     

Functional porous carbons from waste cotton fabrics for dyeing wastewater purification

A new functional porous carbons (PC-WF) is prepared by activation-pyrolysis method use waste cotton fabrics (WF) as an abundant, cheap and available precursor for removal of Brilliant Crocein (BC-GR) and Cationic Red 2GL (CR-GL) from aqueous phase. The PC-WF was characterized by BET, FTIR, SEM, and XRD techniques, the surface area, total pore volume, average pore diameter was found as 1463.5 m² g^-1, 0.783 cm³ g^-1 and 2.14 nm, respectively. The influences on BC-GR and CR-GL adsorption of various experimental factors such as initial concentration and temperature were investigated. Adsorption kinetics was found to be best represented by the pseudo-second order model. The adsorption capacity was 319.8 mg g^-1 for BC-GR and 842.5 mg g^-1 for CR-GL at 30 °C, respectively. The results indicate that for waste cotton fabrics in particular, the practical application of this process to the production of porous carbon would be possible.     

Structural characterization of LbL assembled multilayers by using different polyelectrolytes on cotton fabrics

An alternative approach to application of chitosan based on layer by layer (LbL) assembled technique is studied in this paper. For this aim, chitosan (CHT) was used as a bio-based cationic polyelectrolyte and pentasodium tripolyphosphate (TPP) and poly(sodium 4-styrene sulfonate) (PSS) were selected as anionic polyelectrolyte. TPP/CHT and PSS/CHT based bilayers were fabricated on the cationized woven cotton fabrics via layer-by-layer self-assembly technique. The characterization of coatings on the fabric surface in terms of surface appearance, atomal content, and chemical bondings were made in detail through SEM, XPS, and FTIR-ATR analysis. Also, the antibacterial activity, air permeability, and water contact angle were measured. Surface analyses demonstrate the interaction between TPP, PSS and chitosan separately. XPS spectra also showed the existence of LbL deposition over cotton substrates in terms of both elemental composition and the presence of different types of bondings on the fabric surface. The antibacterial activity analysis revealed that the modified cotton fabric with the addition of CHT/TPP and CHT/PSS bilayers could increase the degree of inhibition on K. pneumanie and S. aureus bacteria.     

Selection of yarn for the predefined tensile strength of cotton woven fabrics

In order to meet the required strength of a fabric, selection of yarn is difficult because tensile strength of woven fabric depends upon a number of factors. Still, the manufacturers have to use hit and trial method in order to select the yarn for the required tensile strength of fabric. This study was carried out to develop regression equations for the prediction of yarn tensile strength suitable for the predefined strength of cotton woven fabrics. These equations were developed by using empirical data obtained from two hundred and thirty four fabric samples prepared under a systematic plan with different constructions. Prediction proficiency and precision of these regression equations were evaluated by correlation analysis of the predicted and actual warp and weft yarn strength values of another set of thirty six fabric samples. The results show a very strong prediction precision of the equations.     

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.     

UV-induced coloration of cotton fabrics by photografting of acrylamido dyes using acrylamide as a comonomer

Formulations of acrylamido dyes containing comonomers can be photografted onto cotton fabric upon UV irradiation at room temperature without neutral salts, which makes it a novel coloration process of excellent environmental friendliness. The photografting of the dyes can be assisted by the copolymerization of the acrylamide comonomer which may reduce the steric hindrance of the bulky dyes. About 90 % of the dyes and 94 % of the acrylamide are photopolymerized in the solution and the degree of polymerization is estimated to be 13.2 according to ¹H-NMR and MALDI-TOF mass analyses. The optimal K/S values of the grafted cotton fabrics showed 13.3 and 12.3 for red and yellow dyes, respectively. The optimal UV-grafting coloration can be achieved when a UV energy of 25 J/cm² was irradiated on the padded fabrics with a formulation of 0.65 mole ratio of acrylamide to the dyes, 7 wt% acetophenone photoinitiator (Irgacure 2959) based on the dye weight under pH 6. Furthermore, the color fastness properties of the grafted fabric were superior to those of conventional reactive dyeing of the dyes due to higher molecular weight of the polymerized dyes.     

Performance of cotton single yarns and knitted fabrics produced by a 2-step spinning method

A low torque spinning method has been recently developed by integrating the ring spinning process with false twisting techniques. As a result of false twist and true twist, a novel single yarn of low torque and soft handle is generated. Based on the similar spinning principle, this paper proposed a 2-step spinning method, which is composed of twisting-anduntwisting operation and can be considered as a variant of the low torque spinning method. The proposed spinning method separates the false twisting process into twisting and untwisting processes which are combined in one step in the low torque spinning method. In this paper, physical properties of yarns produced by the proposed spinning method were evaluated and compared with the conventional yarns. Influences of various spinning parameters on the properties of 2-step yarns were also examined. Furthermore, a systematic study of the physical properties of the 2-step yarns and resultant fabrics with respect to the conventional and low torque ones was carried out. The experimental results showed that the 2-step yarns exhibit slightly higher tenacity, lower wet snarl and much less hairiness than the conventional yarns, which, however, are inferior to the low torque yarns, particularly the evenness. The fabrics made by the 2-step yarns show the softest handle feeling, best airpermeability and moderate spirality angle with acceptable pilling resistance.     

Antimicrobial,UV-protective and self-cleaning properties of cotton fabrics coated by dip-coating and solvothermal coating methods

Multifunctional textiles have been widely investigated with antimicrobial, self-cleaning, UV-protective properties, etc. Especially sol-gel coating doped with bioactive agents and special agents provides to produce multifunctional textiles. In this study, dip-coating (pad-dry) and solvothermal (exhaustion) sol-gel processes were used for coating of cotton fabric with silica and titania sols to achieve the properties mentioned above. A quaternary ammonium salt and silver salts as antimicrobial doping agent were embedded in titania sols with or without silica. Antimicrobial properties against Staphylococcus aureus (S. aureus) of the coated fabrics were characterized. The effect of precursors, doping agents and different sol-gel processes were also compared on performance properties of the fabric samples.     

Synthesis of ZnO nanoparticles by PNP and its application on the functional finishing of cotton fabrics

This paper presents a facile and novel approach for the synthesis of ZnO nanoparticles in aqueous solution based on a one-step reaction between a modified hyperbranched polymer (PNP) and zinc nitrate. The prepared ZnO nanoparticles polymeric hybrid was characterized and its antibacterial activity was investigated. The results indicated that the ZnO nanoparticles have an average size about 6 nm and well dispersed in aqueous medium. The minimum inhibitory concentration (MIC) of them was 20 ppm and 60 ppm against S. aureus and E. coli, respectively. For the functional finishing of cotton fabrics by these ZnO nanoparticles, a microwave assisted in situ fabrication method was employed. Scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) measurements confirmed that the ZnO nanoparticles in situ generated in cotton fabrics successfully. Fourier transform infrared (FT-IR) spectroscopic investigation demonstrated that the ZnO nanoparticles were fixed on the cotton fibers by PNP. The treated cotton fabrics exhibited excellent UV protective properties and antibacterial activities. When ZnO content of cotton fabric was 1.49 %, the UPF value of treated cotton fabric exceeded 125 and the bacterial reduction rate against S. aureus and E. coli reached 99.97 % and 98.40 %, respectively.     

Synthesis and characterization of polyacrylate sizes modified by nano-microspheres prepared via miniemulsion polymerization

This paper firstly stated the fabrication of silica particles via Sol-Gel method and their modification by Silane coupling agent ??-MPS (3-Methacryloxypropyltrimethoxysilane). Pure PSt (Polystyrene) and silica/PSt microspheres were prepared via miniemulsion polymerization. We added these two microspheres to SX-5 size respectively to form the nanomodified sizes. These nano-particles were characterized by means of FTIR (Fourier Transmission Infrared Spectroscopy), DLS (Dynamic Light Scattering) and TEM (Transmission Electron Microscope). Then the properties of sizes (SX-5, nanomodified SX-5, PVA (Polyvinyl Alcohol) 1799), size films, sized yarns, and removability of sizes were characterized. Experimental results show that silica/PSt modified SX-5 had the best properties of sizes, and the best properties presented in size films and sized yarns. This result can be suggested that small size effect, high fluidity, high surface energy and tough surface morphology of silica/PSt microspheres, playing a role as cross-linker and reinforcement, will enhance the mechanical properties of SX-5 and increase the interfacial adhesion force between sizes and yarns.     

Removal of methylene blue by amidoxime polyacrylonitrile-grafted cotton fabrics: Kinetic,equilibrium, and simulation studies

In this study, an amidoxime-grafted cotton fabric ion exchanger was developed for methylene blue (MB) removal from wastewater. The ability of the amidoxime-grafted cotton fabrics to remove MB ions from an aqueous solution was investigated in equilibrium, kinetics and thermodynamics studies. Equilibrium data agreed well with the Freundlich and Langmuir isotherm models. The result indicated that, based on the Langmuir coefficient, the maximum capacity (monolayer saturation at equilibrium) of the amidoxime-grafted cotton fabric was 22.27 mg/g. The kinetic data were found to follow the pseudo-second-order model, and intra-particle diffusion is the sole rate-controlling factor. Negative values of ΔG ⁰, ΔH ⁰, and ΔS ⁰ revealed the spontaneous, exothermic and entropy-driven nature of the process.     

Selective separation of bifenthrin by pH-sensitive/magnetic molecularly imprinted polymers prepared by pickering emulsion polymerization

Via Pickering emulsion polymerization, pH-sensitive magnetic molecularly imprinted polymers (HM-MIPs) were synthesized using bifenthrin (BF) as the template molecule, and pH-sensitive monomer methacrylic acid as the functional monomer. Characterizations of HM-MIPs were achieved by FTIR, TGA, TEM, SEM, and VSM, and the results indicated that HM-MIPs exhibited magnetic property (Ms=1.06 emu/g). HM-MIPs were acted as the adsorbent for a series of adsorption performance testing of BF. Equilibrium data were described by the Langmuir and Freundlich isotherm models. Kinetic properties were successfully investigated by pseudo-first-order model, pseudo-second-order model. The selective recognition experiments exhibited outstanding selectively adsorption effect of the HM-MIPs for target BF over diethyl phthalate and fenvalerate. In water, the HM-MIPs could achieve the adsorption and release of BF by controlling the pH value of the aqueous solution. The results indicated that the molecularly imprinted polymers exhibited good adsorption, selectivity and pH-sensitive performance for BF.     

Objective measurement of hand properties of plasma pre-treated cotton fabrics subjected to flame-retardant finishing catalyzed by zinc oxide

In the present paper, flame resistance property is imparted to cotton fabrics by N-methylol dimethylphos-phonopropionamide (Pyrovatex CP New, FR), melamine resin (Knittex CHN, CL), phosphoric acid catalyst (PA), and ZnO/nano-ZnO co-catalyst. The study shows that effectiveness of the FR-CL-PA reaction to form a crosslinked structure is enhanced by the co-catalytic reaction, resulting in enhancement of fabric’s compressional recovering ability. However, the low pH reaction weakened the fabrics, resulting in poor tensile strength and toughness, stiffer hand feel, brittle and tendered polymer layers, a less spongy fabric structure, and a roughened fabric surface with fuzzy fibrils. In addition, atmospheric pressure plasma jet (APPJ) was used to enhance materials properties by sputtering or etching effect. The roughening effect of plasma treatment enhances tensile properties of treated specimens. Nevertheless, the positive effect is negligible after post-treatment with flame-retardant agents. Moreover, the increased inter-yarn friction enhances the subjective stiffness of fabric and the rigid effect is even worse for plasma pre-treated cotton specimens subjected to flame-retardant treatment. However, plasma pre-treated specimens have a compressible structure after post-treatment with flame-retardant agents. Moreover, neutralization of flame-retardant-treated specimens helps minimize side effects of acidic finishing, irrespective of tensile and compression properties. The process also minimizes shear and bending rigid effect by removing unattached metal oxides from the fabrics.