Effect of CO2 laser treatment on cotton surface

In this study, CO₂ laser was used for treating cotton fabric to create surface effects which were found to vary with laser process parameters, i.e. resolution and pixel time. The resolutions used were 40, 50 and 60 dpi while the pixel time used were 100, 110 and 120 μs. Both physical and chemical properties at the surface of fabrics treated with different combinations of resolution and pixel time were analysed by the Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection mode (FTIR-ATR), and X-ray Photoelectron Spectroscopy (XPS). SEM investigation revealed the appearance of various numbers of pores, cracks and fragments present on the fibre surface after laser treatment. FTIR-ATR spectra showed that the laser-treated cotton fabric suffered changes in chemical structure with the hydroxyl (–OH) stretching group being oxidised to carbonyl/carboxyl groups. The XPS analysis revealed a change in surface elemental composition after laser treatment. Furthermore, the wicking property of the laser-treated cotton fabrics was evaluated.     

The antimicrobial activity of the cotton fabric grafted with an amino-terminated hyperbranched polymer

An amino-terminated hyperbranched polymer (HBP-NH₂) was grafted to cotton fabric by a reaction between the aldehyde groups of oxidized cotton fabric and the amino groups of the HBP-NH₂ to provide cotton fabric with durable antimicrobial properties. The antimicrobial activities of the HBP-NH₂ aqueous solutions and the HBP-NH₂ grafted cotton fabrics were evaluated quantitatively against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The results indicated that the HBP-NH₂ grafted cotton fabric showed 92% of bacterial reduction to S. aureus and 95% of bacterial reduction to E. coli, respectively. The antimicrobial activities of the HBP-NH₂ grafted cotton fabrics were maintained at over 91% reduction level even after being exposed to 20 consecutive home laundering conditions. Several influence factors, which may affect the amount of HBP-NH₂ grafted onto the cotton fabrics, were also discussed.     

Layer-by-layer assembled thin films based on fully biobased polysaccharides: chitosan and phosphorylated cellulose for flame-retardant cotton fabric

Polyelectrolytes multilayer (PEM) films based on fully biobased polysaccharides, chitosan and phosphorylated cellulose (PCL) were deposited on the surface of cotton fabric by the layer-by-layer assembly method. Altering the concentration of PCL could modify the final loading on the surface of cotton fabrics. A higher PCL concentration (2 wt%) could result in more loading. Attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray analysis directly showed that chitosan and PCL were successfully deposited onto the surface of cotton fabric. In the vertical flame test, the cotton fabric with 20 bilayers at the higher PCL concentration (2 wt%) could extinguish the flame. Microcombustion calorimetry results showed that all coated cotton fabrics reduced the peak heat release rate (HRR) and total heat release (THR) relative to the pure one, especially for (CH0.5/PCL2)₂₀, which showed the greatest reduction in peak HRR and THR. Thermogravimetric analysis results showed that the char residue at temperatures ranging from 400 to 700 °C was enhanced compared to that in the pure cotton fabric, especially in the case of higher PCL concentration (2 wt%). The work first provided a PEM film based on fully biobased polysaccharide, chitosan and PCL on cotton fabric to enhance its flame retardancy and thermal stability via the layer-by-layer assembly method.     

Preparation and characterization of flame‐retardant lamellar Mg(OH)2 thin films on citric acid‐treated cotton fabrics

Preparation and characterization of lamellar magnesium hydroxide (Mg(OH)₂) thin films on cotton fabrics are reported in this paper. Mercerized cotton fabrics were treated with citric acid, so carboxyl groups were introduced to the surface of the fabrics. Mg(OH)₂ seeds were first adsorbed on the citric acid‐treated cotton fabrics and then Mg(OH)₂ thin films grew on the fabric through secondary growth method. Kinetics and isotherm studies found that the adsorption of Mg(OH)₂ seeds on citric acid‐treated cotton fabrics followed pseudo second‐order kinetic model and Langmuir isotherm. This indicated that Mg(OH)₂ seeds adsorption was monolayer chemical adsorption driven by electric attraction between positively charged Mg(OH)₂ seeds and ? COO^? ions on the cotton fiber surface. The X‐ray diffraction (XRD) and SEM characterizations of the Mg(OH)₂ thin films covered cotton fabrics found that standing flaky Mg(OH)₂ crystals formed a shell of porous but continuous network on cotton fabric surface. Owing to the Mg(OH)₂ thin film covering, the fabric had fireproof property, lower thermal conductivity and higher optical absorbance in the UV, Vis and IR regions. Copyright © 2010 John Wiley & Sons, Ltd.     

Functionalization of cotton fabrics with rutile TiO<Subscript>2</Subscript> nanoparticles: Applications for superhydrophobic,UV-shielding and self-cleaning properties

The superhydrophobic cotton fabrics were prepared by combining the coating of titanium dioxide (TiO₂) with the subsequent dodecafluoroheptyl-propyl-trimethoxysilane (DFTMS) modification. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements revealed that the nanosized TiO₂ sphere consisted of granular rutile. The TiO₂ layer coated on the cotton altered both the surface roughness for enhancing the hydrophobicity and UV-shielding property. The cotton fabric samples showed excellent water repellency with a water contact angle as high as 162°. The UV-shielding was characterized by UV-vis spectrophotometry, and the results indicated that the fabrics could dramatically reduce the UV radiation. The photocatalytic progress showed that organic stains were successfully degraded by exposure of the stained fabric to UV radiation. Such multifunctional cotton fabrics may have potentials for commercial applications.     

Comparison of copolymer emulsions of fluorine and siloxane‐containing acrylates with core–shell structure for water‐repellent cotton fabrics coatings

This paper described the synthesis of copolymer emulsions of fluorine and siloxane‐containing acrylates for water‐repellent cotton fabrics coatings. Chemical composition, morphology structure, and properties of the latex copolymers were investigated by Fourier transform infrared (FTIR), dynamic light scattering (DLS), gel permeation chromatography (GPC), and transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Effects of water‐repellent functional monomers (R_f) on surface morphology, water contact angle, and water‐repellent properties of the coated fabric surface were also studied. The results indicated that R_f greatly influenced molecular mass distribution of the latex copolymers, the molecular aggregation states and orientation of R_f on the coated fabric surface, and water‐repellency of coated cotton fabrics. Copyright © 2014 John Wiley & Sons, Ltd.     

Combustion pathway of cotton fabrics treated by ammonium sulfate as a flame-retardant studied by TG

The effect of ammonium sulfate (NH₄)₂SO₄ on the flammability of 100% cotton woven fabric (plain 144 g m⁻², the number of yarns 21 per 10 mm) has been of interest in this study. The laundered bone-dried, massed fabrics were impregnated with suitable concentration of aqueous ammonium sulfate solutions by means of squeeze rolls, drying and conditioning. Afterwards the specimen’s resistance to burning has been determined. The optimum add-on value of ammonium sulfate to impart flame-retardancy to cotton fabric was in a range about 10.55–13.62 g anhydrous salt per 100 g fabric. Thermogravimetry (TG/DTG) of the pure cotton and the treated one with the above-mentioned sulfate as well as for pure salt were also accomplished and their TG curves were compared and commented to detect the combustion’s pathway of the supported substrate. TG data confirm major mass loss in treated cotton. It occurred well below at a punctual duration of the thermal degradation zone of the polymer. So fewer flammable volatiles and more char could be produced during combustion. The results obtained are in compliance with gas dilution theory and also chemical action theory.     

Coating Cellulosic Material with Ag Nanowires to Fabricate Wearable IR-Reflective Device for Personal Thermal Management: The Role of Coating Method and Loading Level

Textiles coated with silver nanowires (AgNWs) are effective at suppressing radiative heat loss without sacrificing breathability. Many reports present the applicability of AgNWs as IR-reflective wearable textiles, where such studies partially evaluate the parameters for practical usage for large-scale production. In this study, the effect of the two industrial coating methods and the loading value of AgNWs on the performance of AgNWs-coated fabric (AgNWs-CF) is reported. The AgNWs were synthesized by the polyol process and applied onto the surface of cotton fabric using either dip- or spray-coating methods with variable loading levels of AgNWs. X-ray diffraction, scanning electron microscopy (SEM), infrared (IR) reflectance, water vapor permeability (WVP), and electrical resistance properties were characterized. The results report the successful synthesis of AgNWs with a 30 μm length. The results also show that the spray coating method has a better performance for reflecting the IR radiation to the body, which increases with a greater loading level of the AgNWs. The antibacterial results show a good inhibition zone for cotton fabric coated by both methods, where the spray-coated fabric has a better performance overall. The results also show the coated fabric with AgNWs maintains the level of fabric breathability similar to control samples. AgNWs-CFs have potential utility for cold weather protective clothing in which heat dissipation is attenuated, along with applications such as wound dressing materials that provide antibacterial protection.     

Effect of zinc oxide on flame retardant finishing of plasma pre-treated cotton fabric

An organic phosphorus compound (flame retardant agent, FR) in combination with a melamine resin (crosslinking agent, CL), phosphoric acid (catalyst, PA) and zinc oxide (co-catalyst, ZnO/nano-ZnO) imparted effective and durable flame retardant properties. Also, atmospheric pressure plasma jet was applied as pre-treatment to improve post-finishing (flame retardant finishing) on cotton fabrics. In the present paper, surface morphology, chemical structure analysis, combustibility and mechanical properties of plasma pre-treated cotton fabrics subjected to flame-retardant treatment were investigated. Surface morphology of treated cotton specimens showed roughened and wrinkled fabric surface with high deposition of the flame retardant finishing agent, which was caused by the plasma etching effect and attack of acidic FR. The FTIR-ATR spectra for the treated cotton specimens showed some new characteristic peaks in chemical structure, interpreted as carbonyl bands, OH stretching vibration, COO⁻ stretching vibration, CH₂ rocking band and CH₃ asymmetric and CH₂ symmetric stretching. Moreover, FR-CL-PA-treated specimens showed remarkable flame-retardant property, which was further improved by the plasma pre-treatment and ZnO/nano-ZnO co-catalyst. However, flame-retardant-treated cotton specimens had poor mechanical strength when compared with control sample, resulting from side effects of the crosslinking agent used, while plasma pre-treatment and ZnO/nano-ZnO co-catalyst may compensate for the reduction in tensile and tearing strength caused by flame-retardant agents.     

Dynamic and controlled rate thermal analysis of attapulgite

We have investigated the effect of magnesium chloride hexahydrate [MgCl₂·H₂O] as a nondurable finish on the flammability of 100% woven cotton fabric, (plain construction, with a density of 144 g m⁻², the number of yarns 21/10 mm). The laundered bone-dried, massed fabrics were impregnated with suitable concentrations of aqueous solution of the above-mentioned salt, by means of squeeze rolls. They were then dried horizontally in an oven at 110°C for 30 min. The optimum add-on value after the fulfillment of vertical flame spread test to donate flame-retardancy onto cotton fabric was obtained to be in the range of 6.73–8.30 g of the salt per 100 g fabric. Thermogravimetry (TG) of pure cotton, treated cotton and the salt was accomplished, and their TG curves were compared and commented. The results obtained are in favor of the ‘gas dilution theory’, chemical action theory and also in compliance with the ‘free radical theory’. The formation of sal ammoniac was proven by sprinkling concentrated ammonia upon the inflamed treated specimen.     

Asymmetrically superhydrophobic cotton fabrics fabricated by mist polymerization of lauryl methacrylate

A graft-polymerization process with atomized lauryl methacrylate as monomer is used to fabricate fluorine-less and asymmetrically superhydrophobic cotton fabrics. The polymers synthesized in the process can form nanoscale hierarchical structures on the cotton surface, and the surface morphology can be controlled by choosing a suitable solvent or by varying the feeding quantity of the monomer mist stream. After applying the surface modification to cotton fabrics, an asymmetrically superhydrophobic surface is achieved without any additional nanosized particles, and the solvent damages on the cotton fabrics are controllable at a very low level. Surface characterization reveals that the modified side of the cotton fabric has laundering-durable and mechanically stable superhydrophobicity with a water contact angle of more than 150°, whereas the opposite inherits the hydrophilic property of pristine cotton fabric. The modified cotton fabrics are found to have medium-level water-absorbing ability between pristine cotton and PET fabrics, as well as good vapor transmissibility similar to pristine cotton fabric. These properties are of great significance in textile and medical applications.     

Production,Partial Characterization,and Use of a Red Biochrome Produced by <Emphasis Type="Italic">Serratia sakuensis</Emphasis> subsp. nov Strain KRED for Dyeing Natural Fibers

We have described a novel red biochrome, 514 Da in size, produced by solid-state cultivation of a bacterial isolate obtained from garden soil. The growth requirements of the isolate, the chemical characteristics of the biochrome produced, and the application of the biochrome in dying of silk, wool, and cotton fabrics have been studied. The biochrome obtained after 52 h of incubation and having a λ _max of 535 nm was used for dyeing the fabrics. We found that silk, wool, and cotton fabrics dyed with this new natural red compound have high color strength values and dye uptake along with good color fastness as well as antibacterial activity.     

Effects of TiO<Subscript>2</Subscript> on the hydrophilicity of сotton/polyester (50/50) blend fabric under UV irradiation

Alkaline TiO₂ nanoparticles treated cotton/polyester (50/50) blend fabric were prepared, and then exposed to UV irradiation. It was found that the addition of a small amount of TiO₂ nanoparticles to the coating solution improves the hydrophilicity and mechanical strength of the fabrics. The treated fabrics exhibited high water absorption as well as better hydrophilicity compared to the untreated sample. Compared to the surface of untreated blend fabric, scanning electron microscopy showed that the surface of the modified blend fabric becomes rough and covered by a layer of other materials. Furthermore, X-ray diffraction demonstrated the formation of crystalline material. In addition, thermograms showed that the modification process improved the thermostability of blend fabric.     

Preparation of durable superhydrophobic surface by sol–gel method with water glass and citric acid

Durable superhydrophobic surface on cotton fabrics has been successfully prepared by sol–gel method. Cellulose fabric was first coated with silica sol prepared with water glass and citric acid as the acidic catalyst. The silica coated fabric was then padded with hydrolyzed hexadecyltrimethoxysilane afterwards obtaining low surface energy. Water contact angle and hydrostatic pressure were used to characterize superhydrophobicity and washing durability. Scanning electron microscopy was used to characterize the surface morphology changes after certain washing times. All results showed good durable hydrophobicity on cellulose fabrics. In addition, the influence of citric acid and sodium hypophosphite (NaH₂PO₂) on the durability of hydrophobicity was also investigated. The durability of treated cotton improved with the increase of concentration of citric acid in the presence of NaH₂PO₂. It could be concluded that citric acid acted as multi-functional heterogeneous grafting chemicals to improve washing durability of hydrophobicity by forming the ester bonds between cotton fabric and silica sol and improved the durability of hydrophobicity.     

A simple method for determining the total amount of physically and chemically bound water of different cements

A novel environmentally friendly flame-retardant compound, diethyl 3-(triethoxysilanepropyl) phosphoramidate (DTP) was synthesized via a simple one-step procedure with good yield and characterized by FT-IR and ¹H-NMR, ³¹P-NMR and ²⁹Si-NMR. The synthesized compound was coated onto cotton fabrics with different levels of add-ons (5–17 mass%) using the traditional pad-dry-cure method. SEM and XPS were conducted to characterize the surfaces of the coated cotton fabrics. The XPS results showed that DTP was attached to cotton through covalent bond. Cone calorimeter test showed that the cotton fabric treated with DTP became less flammable due to the lower HRR, THR and CO₂/CO ratio. The modified cotton fabrics exhibited efficient flame retardancy, which was evidenced by limiting oxygen index (LOI) and vertical flammability test. Cotton fabrics treated with DTP in 5–17 mass% add-ons had high LOI values of 23–32%. Thermogravimetric analysis results show that the usage of DTP promotes degradation of the cotton fabrics and catalyzes its char formation.     

In-situ growth of silica nanoparticles on cellulose and application of hierarchical structure in biomimetic hydrophobicity

Monodispersed silica nanoparticles were prepared by a simple two-step method with hydrolysis and condensation. The materials were characterized by dynamic light scattering (DLS), SEM and TEM. Through in-situ growth of silica nanoparticles on cotton fabrics, a dual-scaled surface with nanoscaled roughness of silica and microscaled roughness of cellulose fiber was generated. After the modification of the low surface energy, the wettability of smooth silicon slide, silicon slide with nanoscaled roughness of silica particles, cotton fabric, and cotton fabric with silica particles was evaluated by the tests of the contact angle (CA) and the advancing and receding contact angle (ARCA). The cotton fabric with dual-scaled roughness exhibits a static CA of 149.8° for 4 μL water droplet and a hysteresis contact angle (HCA) of 1.8°. The results of CA and HCA show that microscaled roughness plays a more important role than nanoscaled roughness for the value of CA and HCA. The results in the hydrostatic pressure test and the rain test show the important contribution of nanoscaled roughness for hydrophobicity.     

Using graphene/TiO2 nanocomposite as a new route for preparation of electroconductive,self-cleaning,antibacterial and antifungal cotton fabric without toxicity

A novel and efficient process is reported for fabrication of electroconductive, self-cleaning, antibacterial and antifungal cellulose textiles using a graphene/titanium dioxide nanocomposite. Cotton fabric was loaded with graphene oxide using a simple dipping coating method. The graphene oxide-coated cotton fabrics were then immersed in TiCl₃ aqueous solution as both a reducing agent and a precursor to yield a fabric coated with graphene/titanium dioxide nanocomposite. The crystal phase, morphology, microstructure and other physicochemical properties of the as-prepared samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and UV-Vis reflectance spectroscopy. Electrical resistance, self-cleaning performance, antimicrobial activity and cytotoxicity of treated fabrics were also assessed. The electrical conductivity of the graphene/titanium dioxide nanocomposite-coated fabrics was improved significantly by the presence of graphene on the surface of cotton fabrics. The self-cleaning efficiency of the treated fabrics was tested by degradation of methylene blue in aqueous solution under UV and sunlight irradiations. The results indicated that the decomposition rates of methylene blue were improved by the addition of graphene to the TiO₂ treatment on fabrics. Moreover, the graphene/titanium dioxide nanocomposite-coated cotton samples had negligible toxicity and possessed excellent antimicrobial activity.     

Bactericidal activity and UV-filtering property of TiO<Subscript>2</Subscript>-based photocatalysts coated on curtain fabrics

Synthesized and commercial titanium dioxide (TiO₂) were coated onto household curtain fabrics for anti-microbial and ultraviolet (UV) shielding functions. The coating was performed by inducing a deposition of the TiO₂ layer from the Ti precursor onto the fabric surface. A silane adhesive agent was employed to improve the adhesion between the coating and the fabric. Ag nanoparticles were also incorporated into some samples to further improve the anti-bacterial activity, which was evaluated by a standard qualitative test (AATCC 147). Efficiency for UV shielding was evaluated by measuring a UV–visible reflection of the coated fabrics both before and after subjecting it to several washing cycles. The results showed that the TiO₂-coated fabrics had potential as both anti-bacterial and UV shielding for the curtain industry.     

Functionalization of cotton fabrics with corona/air RF plasma and colloidal TiO2 nanoparticles

This study discusses the possibility of using a corona discharge at atmospheric pressure and air RF plasma at low pressure for the cotton fibre activation prior to deposition of colloidal TiO₂ nanoparticles in order to enhance antibacterial, UV protective and self-cleaning properties. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of TiO₂ nanoparticles on the surface of cotton fibres. XPS elemental mapping indicated that TiO₂ nanoparticles were more evenly distributed across the surface of untreated and corona pre-treated cotton fabrics in comparison with RF plasma pre-treated fabric. Atomic absorption spectroscopy measurements revealed that the equivalent total content of TiO₂ in the cotton fabrics pre-treated by corona and RF plasma was 31% higher than in the fabric that did not undergo any treatment prior to loading of TiO₂ nanoparticles. In order to achieve maximum bacteria (Gram-negative bacteria Escherichia coli) reduction, untreated cotton fabric had to be loaded with colloidal TiO₂ nanoparticles twice, but only once following corona or RF plasma pre-treatment. Deposition of TiO₂ nanoparticles onto cotton fabrics provided maximum UV protective rating of 50+. Extraordinary photocatalytic activity of TiO₂ nanoparticles deposited onto cotton fabrics was proved by self-cleaning of blueberry juice stains and photodegradation of methylene blue in aqueous solution under UV illumination.     

Antibacterial cotton fabric prepared by a “grafting to” strategy using a QAC copolymer

Quaternary ammonium compounds (QACs) have outstanding antimicrobial effect, but covalent immobilization of plentiful QAC onto cotton fiber surface to realize a durable function remains a challenge. Herein, a quaternary ammonium monomer, [2-(methacryloyloxy) ethyl] trimethylammonium chloride (DMC) was co-polymerized with methyl acrylate (MA) to prepare an antibacterial copolymer, poly(DMC-co-MA). To graft the copolymer with an improved grafting efficiency, cotton fabric was treated using carboxymethyl chitosan (CMC) to establish an amino-functionalized fiber surface first. This treatment allows the amidation reactions between the amino groups and the pendant ester groups in the poly(DMC-co-MA) to take place, achieving a durable anionic polymer coating onto the fiber surfaces with remarkably antibacterial effect. Characterization results indicated that when DMC/MA monomer ratio was 100:1, the resulting copolymer endows the modified cotton fabric with antibacterial capability that inactivates all Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Even after 50 laundering cycles, more than 98.0% of the antibacterial rate could still be retained. Moreover, the wearing comfort properties such as softness, water absorption and air permeability of the finishing cotton fabrics have been insignificantly changed by comparing to the untreated cotton fabric.