Experimental investigation on the thermal protective performance of nonwoven fabrics made of high-performance fibers

In this study, the thermal protective performance of nonwoven fabrics made of Nomex (polyisophthaloyl metaphenylene diamine), PPS (polyphenylene sulfide), P84 (polyimide), and basalt fibers was investigated. The objective was to determine the influence of fiber type, thickness of fabric, and wet on the thermal protective performance of nonwoven fabric. The thermal resistances of different nonwoven fabrics were measured using a dry hot plate instrument, the basalt nonwoven fabrics had a highest thermal resistance in all fabric, and the thermal resistance of nonwoven fabric increased with the increase in thickness. The six nonwoven fabrics were exposed to a hot environment for a few minutes by using a self-designed apparatus. The test results showed that the nonwoven fabrics made with basalt fiber exhibited the best thermal protective performance, and the thermal protective abilities of nonwoven fabrics increased with fabric thickness. Interestingly, nonwoven fabrics with added water were found to be able to keep the fabric surface lower temperature compared to dry fabrics when exposed to a hot environment, indicating the excellent thermal protective performance of wet nonwoven fabrics.     

Photo-induced chemiluminescence from fibrous polymers and proteins

A commercial thermal chemiluminescence (TCL) instrument was modified to allow in situ sample irradiation at wavelengths in the range 320-700 nm under a controlled atmosphere at constant temperature. Weak photo-induced chemiluminescence (PICL) emission was observed from commercial poly(ethylene terephthalate), polyacrylonitrile, and polyamide 6 fabrics, cotton fabric and from the fibrous proteins wool and feather keratin, silk fibroin and bovine skin collagen (Type 1) after exposure to UVA (320-400 nm) or visible light in nitrogen, followed by a change of the atmosphere to oxygen. Collagen emits PICL of similar intensity to keratin, which demonstrates that tryptophan is not essential for PICL emission from proteins. In all cases the decay of PICL with time is complex and does not follow simple first- or second-order kinetics. The effects of experimental variables, including wavelength of radiation and exposure time, sample temperature and fabric pH on the PICL intensity and decay profile are reported for wool keratin.     

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.     

Vapor phase polymerization of 3,4‐ethylenedioxythiophene on flexible substrate and its application on heat generation

An oxidative chemical vapor phase polymerization process is applied to coat flexible polyethylene terephthalate (PET) fabrics with a uniform poly(3,4‐ethylenedioxythiophene) (PEDOT) film. This vapor phase polymerization method is a solventfree technique, which could yield a low resistance in the PEDOT‐coated PET fabric. The resistance as low as 52 Ω square^?1 is achieved. The polymerization conditions, such as the concentration of oxidant, reaction time, and temperature, have been systematically investigated. The coated fabric samples exhibit an increase in temperature when subjected to a fixed DC voltage. This result indicates a potential application of these PEDOT‐coated fabrics as electric heating materials. Copyright © 2009 John Wiley & Sons, Ltd.     

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.     

Durable,water-cleanable,superhydrophilic coatings for oil/water separation under harsh conditions

A simple, economical, and efficient method for fabricating stable hydrophilic/underwater superoleophobic coating under harsh conditions remains a significant challenge. Here, by the hydrolysis of 3-(Methacryloyloxy) propyltrimethoxysilane (TMSPMA) on cotton fabric and the free radical polymerization of [2-(Methacryloyloxy) ethyl] dimethyl-(3-sulfonic acid propyl) ammonium hydroxide (SBMA) and TMSPMA, a superhydrophilic coating was fabricated. The coating can withstand harsh environments, such as strong acid and alkali. In addition, the coated cotton fabrics show an effective separation of surfactant-stabilized oil-in-water emulsions with extreme flux as high as 1500 Lm^?2 h^?1 only under gravity. Importantly, the oil-contaminated coated cotton fabrics can be cleaned only by water washing. The outstanding properties of the coating including durability, recyclability and resistance to harsh environment, highlight its practical application in emulsion separation and oily wastewater purification.     

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.     

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.     

Thermal transport characteristics of polypropylene fiber-based knitted fabrics

Thermal comfort is condition of an organism, when there is no sweating and the mean skin temperature is in the range from 32 to 34?°C (Hes, Measurement of comfort, What can textile III, 2009). Thermal comfort is closely connected with the following characteristics: thermal resistivity and thermal conductivity. Related properties are: resistance against the penetration of water vapor, air permeability, and porosity. The thermal resistivity R (W^?1?K?m²) and thermal conductivity K (W?K^?1?m^?1) of knitted fabrics containing PP fiber were measured. Measurements were realized on three different types of devices. The experimental results were compared with simple mechanistic model for prediction of thermal conductivity K for textile structures.     

Imparting durable antimicrobial properties to cotton fabrics using quaternary ammonium salts through 4-aminobenzenesulfonic acid-chloro-triazine adduct

A 4-aminobenzenesulfonic acid-chloro-triazine adduct was successfully synthesized in a laboratory scale and treated with cotton fabrics in order to increase the anionic sites and thereby % exhaustion of cationic compounds. Two Quaternary Ammonium Salts (QAS) was investigated namely, Cetylpyridinum chloride (CPC) and Benzyldimethylhexadecyl ammonium chloride (BDHAC) which are widely accepted as strong antimicrobial agents. The reaction mechanism involved in the synthesis of the reactive adduct as well its application to cotton fabric were demonstrated in detail. The effects of application parameters, namely pH, temperature and liquor ratio were examined. The reaction efficiency was determined through monitored % exhaustion of the adduct by cotton fabric. Antimicrobial activity of the treated cotton sample was studied against Staphylococcus aureus according to AATCC test method 100-1999. Results obtained show that the treated fabric shows higher antimicrobial activity compared with the untreated fabric. The results depict also that % exhaustion decreases as the pH, temperature and liquor ratio increase. Moreover, the appropriate predictable empirical models were developed using Excel solver function incorporating interaction effects of all variables to predict the % exhaustion and the satisfactory results (R² > 0.98) were obtained.     

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.     

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.     

Thermodynamic interactions of natural and of man-made cellulose fibers with water

The vapor pressure of water was measured for binary mixtures with cellulose containing fabrics at 37 °C by means of two complementary methods. Different types of fabrics were studied: One consisting exclusively of cellulose fibers, either of natural origin (cotton) or regenerated from solutions in the mixed solvent NMMO/water (Lyocell fibers, CLY) and another kind of fabric containing polyethylene terephthalate (PET) fibers in addition to CLY fibers. The Flory-Huggins interaction parameters χ and their composition dependence calculated from these vapor pressure data are broadly similar for cotton and for CLY, apart from the fact that water interacts somewhat more favorably with CLY than with cotton. In both cases the χ values pass successively a maximum and a minimum as the concentration of water rises. The experiments performed with the fabrics containing two types of fibers demonstrate that the water uptake of PET is negligible as compared with that of cellulose. The results for the system water/cellulose fibers obtained at 37 °C differ fundamentally from corresponding data for 80 °C, reported for cellulose films prepared from solutions in dimethylacetamide + LiCl. The maximum water uptake of cellulose is determined by its degree of crystallinity. In all cases it is possible to model the Flory-Huggins interaction parameters as a function of composition quantitatively by means of an approach subdividing the dilution process conceptually into two separate steps: Contact formation between the dissimilar components (keeping their conformation constant) and subsequent relaxation of the system into the equilibrium state. Similarities and dissimilarities of the systems water/polysaccharide are being discussed in detail.     

Superhydrophobic properties of cotton woven fabrics with conducting 3D networks of multiwall carbon nanotubes,MWCNTs

This article presents the findings concerning the preparation and properties of cotton woven fabrics with a conductive network made of multiwall carbon nanotubes deposited on the fiber surface by the padding method. The next stage of treatment consisted of imparting superhydrophobic properties to the fabrics in solution with methyltrichlorosilane (MTCS) in a waterless medium. The tests performed show that the state of surface and water content in cotton fibers exerts a significant influence on the hydrophobic properties of the analyzed samples. In order to explain the differences in hydrophobic properties, the morphology of the cotton fabric surface was examined using samples with various water contents. The formation mechanism of MTCS coatings on cotton fabric has been proposed.     

Novel UV-protective formulations for cotton, PET fabrics and their blend utilizing irradiation technique

A novel coating formulation to impart ultraviolet (UV) protection property to cotton, Polyethylene trephethalate (PET) and cotton/PET fabrics was prepared and gamma rays as an ionizing radiation was utilized for surface curing. Natural occurring aluminum potassium sulfate (Alum) was used individually and in binary coat with Zinc Oxide (ZnO), to induce the UV-blocking properties. It was found that using Alum (0.3 g/ml) caused a prompt increase in ultraviolet protection factor (UPF) over the uncoated fabrics. Moreover, the incorporated ZnO in the binary coat increased the UPF for two to threefold than the stand-alone Alum coating, specially in case of PET coated fabric. Water absorbance and moisture regain of ZnO and Alum/ZnO coated fabrics showed a decrease over the blank samples, due to the usage of oligomer/monomer combination. On contrary, Alum showed a hydrophilic effect with the increase in its content in the formulation. Surface Electron Microscope showed the homogenous coating of fibers. X-ray diffraction (XRD), energy dispersive X-ray (EDX) and water vapor permeability were also tested for coated samples.     

含氟环氧树脂杂化纳米二氧化硅超疏水材料的制备与性能

目前超疏水材料的制备方法大都存在着制备工艺复杂的缺点。 本文采用传统自由基聚合方法,以甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St)为单体,合成具有交联性的前驱聚合物P(GMA-r-St)。 再用三氟乙酸(TFA)对其进行接枝改性,制备含氟环氧聚合物P(GMA-r-St)-g-TFA。 利用γ-氨丙基三乙氧基硅烷(KH-550)改性纳米二氧化硅(SiO₂),对其进行傅里叶变换红外光谱(FTIR)、热重(TG)表征。 氨基改性的纳米二氧化硅与含氟环氧聚合物混合制备的超疏水改性材料,棉织物表面经其浸泡,可快速构建超疏水结构。 通过改变改性纳米颗粒的含量,探究其构筑的棉织物的疏水性能和耐溶剂性能。 研究结果表明,经浸泡改性的棉织物,水接触角为160°,耐溶剂性时间为130 min,具备很好的耐溶剂性。 该方法可广泛应用于多种基底材料表面的疏水改性。     

In situ production of silver nanoparticle on cotton fabric and its antimicrobial evaluation

An ecological and viable approach for the in situ forming silver nanoparticles (AgNPs) on cotton fabrics has been used. Silver nanocoated fabric of brownish yellow color (AgNPs, plasmon color) was characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR). SEM images revealed that the surface of the modified cotton was rougher than that of normal cotton. In addition, SEM images showed the presence of AgNPs on the surface of the treated fabric. Silver mapping and elemental analysis of the silver nanocoated cotton fabric using EDS confirmed the presence of AgNPs in a homogeneous distribution. Also, FTIR spectra of silver nanocoated sample showed more intense and broad peaks with a slight red shift if compared with those of blank sample indicating the binding of AgNPs with cellulose macromolecules. Different coating levels and the impact of repeated washings have been evaluated against different microbial strains by growth inhibition zone. The results of antimicrobial studies reveal that the presence of a low coating level of nanosilver is enough for producing an excellent and durable antimicrobial cotton fabrics.     

Detection of copper(II) sulfate’s uniformity and its thermal behavior in flammability of cotton fabric

Blue vitriol (copper(II) sulfate pentahydrate), CuSO₄·5H₂O has been chosen and investigated for its effectiveness as a flame-retardant, when impregnated into cotton fabric (cotton with a plain structure; woven 180 g m⁻², with 22 numbers of yarns per 10 mm). Using the vertical flame test, the extent of resistance to burning of the specimens has been determined. The impregnation was accomplished via dipping and stirring of bone-dried, weighed fabrics into the individual and suitable concentrations of the salt at room temperature. Afterwards the samples were squeeze rolled and dried horizontally at 110°C for 30 min in an oven and cooled in a desiccator and reweighed with an analytical precision. They were then kept under ordinary conditions overnight prior the fulfillment of the vertical flame test. The efficient quantities of the aforesaid salt expressed in g per 100 g dry fabric have been determined in an average figure of 12.75%. Estimation of uniformity in a selected sample was carried out via a spectrophotometer and results are in favor of the heterogeneous distribution of the salt in the fabric’s middle sectors. However initial and final parts of specimen showed to be rather uniformed. Thermogravimetric analysis of the pure cotton and the treated ones with insufficient and effective amounts of the salt were fulfilled and their thermograms were compared and commented. The results obtained for the effect of copper(II) sulfate comply with ‘The Dust or Wall Effect Theory’. This action is also assigned to the condensed phase retardation.     

Influence of antimicrobial finishes on the biodeterioration of cotton and cotton/polyester fabrics: Leaching versus bio-barrier formation

The influence of antimicrobial activity of two contemporary finishes, specifically a dispersion of colloidal silver (Ag) and 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC), on the degree of biodeterioration of 100% cotton (CO) fabric and fabric composed of a mixture of cotton and polyester (CO/PET) was studied. Ag was chosen for the leaching agent, while Si-QAC was used as the bio-barrier-forming agent. The biodeterioration of samples finished with different concentrations of Ag and Si-QAC was analysed from a standard soil burial test after 3, 6 and 12 days of exposure to soil microflora. SEM micrographs revealed intensive biodeterioration of the unfinished cellulose fibres, while the highly biologically resistant polyester fibres remained undamaged. A controlled release of Ag successfully inhibited biodeterioration of the cellulose fibres in the CO and CO/PET fabrics when its concentration reached a lethal, biocidal concentration. Contrary to the effects of Ag, the bio-barrier formation of Si-QAC on CO and CO/PET fabrics was insufficient to protect the cellulose fibres during longer periods of soil burial, irrespective of its concentration. Intensive chemical changes to the cellulose were clearly seen from the FT-IR spectra of all of the samples. The resistance of the polyester component to biodeterioration did not provide any significant protection for the cotton component in CO/PET fabric.     

Fabrication of asymmetrically superhydrophobic cotton fabrics via mist copolymerization of 2,2,2‐trifluoroethyl methacrylate

We report here a simple strategy for fabricating asymmetrically superhydrophobic cotton fabric via a mist copolymerization of three monomers, 2,2,2‐trifluoroethyl methacrylate (TFMA), 2‐isocyanatoethyl methacrylate (IEM), and divinylbenzene (DVB). The copolymer layer on the cotton surface was confirmed by X‐ray photoelectron spectroscopy (XPS) analysis and attenuated total reflection (ATR) accessory, and the nanoscale hierarchical structures in the polymeric layer were demonstrated by observation of field emission scanning electron microscope (FE‐SEM). Surface characterization reveals that the modified surface is superhydrophobic, but the opposite side of the modified cotton fabric has the hydrophilic nature of cotton. More experimental data suggest that the good water adsorptivity and vapor transmissibility of the original cotton fabric were inherited after the surface modification. These properties are of great significance in textile and medical applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1862–1871