A study of the thermal properties of bamboo knitted fabrics

In this research, the thermal properties of bamboo single jersey knitted fabrics have been studied in relation to stitch length and yarn linear density in tex. The objective was to determine the influence of fabric factors like stitch length and the constituent yarn linear density on fabric properties, such as air permeability, thermal conductivity, thermal resistance and relative water vapour permeability. Yarns with linear densities of 19.6, 23.6, 29.5 tex and with the same twist level were used to construct the fabrics of single jersey structure with stitch lengths of 0.27, 0.29 and 0.31 cm. The anticipated increase in air permeability and relative water vapour permeability with decrease in yarn linear density and increase in stitch length was observed. The thermal conductivity and thermal resistance tended in general to increase with constituent yarn linear density but decreased with increase in stitch length.     

A novel method for the production of conductive ring spun yarn

To take the advantages of spun yarns such as porosity, softness, bending as well as usability as yarn/fabric forms, this study worked on an alternative conductive yarn production method. Different from widely used application methods, a conductive nanosuspension was applied to viscose, cotton and polyester open fibre bundles with different feeding amounts during the ring spinning with a specially developed apparatus. Reduced graphene oxide (rGO) synthesized with a single step process instead of two-step processes was used to impart conductivity. Following to yarn production, winding, knitting and washing processes were realized to evaluate the changes in yarn conductivity and the usability of the yarns in the post-spinning processes. In addition to tensile properties of the yarns and air permeability of the fabrics, electrical resistance and environmental impact of the method was compared with immersion and drying process. The results indicated that alternative method allows the production of conductive (lower resistance than 100 kΩ) but also strong, flexible, washable and breathable electronic textile products with an environmentally friendly process. There has been no effort, as yet, to get conductivity in this manner. Therefore, the developed method can be considered to be a new application in the functional yarn production field. The produced conductive yarns can be converted into fabric form by weaving, knitting and embroidery. Therefore, they can also be seen as an ideal as the platforms for future wearable electronics.

     

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.     

Investigation of the dyeing properties of cotton fabrics and wool yarns using Prunus persica leaf extract

In this study, the dyeing properties of cellulose fabric and wool yarn were investigated using Prunus persica (Peach) leaf extracts. For this concept, the cotton fabrics and wool yarns were subjected to pre–, meta– and post– mordanting processes in the presence of FeSO₄, CuSO₄ and AlK(SO₄)₂ mordants. The studies were carried out using medium pH. Color analyses of the dyed samples were done and the results were evaluated in terms of wash, rubbing and light fastness values. The color codes were determined with Pantone Color Quide, and K/S and L1 a1 b1 values were detected with color measurement spectrophotometer, and also washing–, crocking– fastness levels were evaluated using gray scale. As a result, it was detected that wool yarns exhibited better dyeing potential than cotton fabrics and highest color strength values were obtained using pre–mordanting method. For wool yarns, high color strength were achieved in the presence of AlK(SO₄)₂ mordant.     

Effect of Blending Factors on Eri Silk and Cotton Blended Yarn and Fabric Characteristics

Eri cocoons were prepared into short fibers and subsequently blended with cotton fiber in order to develop the new fiber blended yarn in the short spinning system. The Eri and cotton fibers were blended using the drawframe blending with varying blending factors, viz. blending composition (0–100%) and yarn counts (30 and 50 tex). The results showed that Eri fiber which was longer and stronger than cotton fiber, affected the fiber distribution in the yarn cross-section. The mechanical properties of the blended fibers and yarns increased with increasing silk content. Longer fibers of Eri silk tended to move towards the yarn core, especially at silk content higher than 50%. Moreover, stronger and more extensible Eri silk fiber gave an advantage to the improvement of mechanical properties of those blended yarns with silk content higher than 50%. However, with increasing silk content, the blended yarns were more irregular as shown in %CV. Concerning the yarn count effect, the higher yarn count of 50 tex resulted in a more regular yarn with higher yarn strength than that of 30 tex. The plain-woven fabrics were prepared using the blended yarns as a weft yarn and the cotton yarn or silk yarn as a warp yarn. The mechanical properties of those woven fabrics were characterized in order to study the influence of silk contents. The results showed that tensile strength, %elongation and tear strength of woven fabrics using the blended yarn were increased with an increase in silk content. This is an advantage of Eri silk in the aspect of rendering the strength to the blended yarns and fabrics.     

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 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.     

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.     

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.     

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.     

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.     

Antimicrobial activity of hydrophobic cotton coated with N‐halamine

γ‐(β‐Hydroxy‐γ‐5,5‐dimethylhydatoin)‐propyltriethoxysilane, a N‐halamine precursor, was synthesized with 3‐aminopropyltriethoxysilane and 3‐glycidyl‐5,5‐dimethylhydantoin. The N‐halamine precursor was tethered to the cotton fabric through ether linkages. The treated fabrics can be rendered excellent antimicrobial activity through a bleaching process. It can inactivate 100% of the Staphylococcus aureus and Escherichia coli O157:H7 with a contact time of 10 min and 30 min, respectively. Over 30% of the chlorine could be regained after the equivalent of 50 machine washes and rechlorination. The coatings resulted in a significant increase of hydrophobicity of cotton samples. In addition, the wrinkle recovery angle of the treated fabrics increased to some degree. Copyright © 2014 John Wiley & Sons, Ltd.     

Silver (I) antimicrobial cotton nonwovens and printcloth

In this paper we discuss the preparation and comparative evaluation of silver (I) [Ag(I)] nonwoven and woven antimicrobial barrier fabrics generated from commercial calcium‐sodium alginates and laboratory prepared sodium carboxymethyl (CM) cotton nonwovens and CM‐cotton printcloth for potential use as wound dressings. Degrees of CM substitution (DS) in cotton nonwoven and printcloth samples by titrimetry were 0.38 and 0.10, respectively. Coordination of Ag(I) with carboxylates on fabrics was effected by ion exchange and nitrates were removed by washing to mitigate nitrate ion toxicity issues. Durability of silver coordinated fabrics was tested by soaking them in deionized water with slight agitation at 50°C. Ag(I) alginates and nonwoven Ag(I)‐CM‐cottons lost structural integrity in water. Ag‐CM‐cotton printcloth samples retained structural integrity even after four soak‐and‐dry cycles, were smooth to the touch when dry, and were smoother when moistened. They could be easily peeled from wound surfaces without inducing trauma. Solid‐state carbon‐13 (¹³C) nuclear magnetic resonance (NMR) spectrometry was used to observe changes in carbonyl resonances in Ag(I) alginates and Ag(I)‐CM‐printcloth, and the chemical shift positions of carbonyl resonances of uncoordinated and Ag(I) coordinated fabrics did not change. Inductively coupled plasma‐mass spectrometry (ICP‐MS) was used following fabric digestion to determine the total Ag(I) ion content in fabrics. Ag(I) alginates were found to hold about 10–50 mg Ag(I) per gram fabric; and Ag(I) cotton woven and nonwoven fabrics held about 5–10 mg Ag(I) ions per gram fabric. Kinetic release of Ag(I) after soaking once in physiological saline was studied with ICP‐MS to estimate the availability of Ag(I) upon a single exchange with Na(I) ions on wound surfaces. Alginates released between ～13 and 28% of coordinated Ag(I), and CM‐cotton nonwovens and CM‐cotton printcloth released ～14 and 3% of coordinated Ag(I) ions, respectively. Finally, Ag(I) alginates and Ag(I)‐CM‐cotton printcloth samples were evaluated against Gram‐positive Staphylococcus aureus and Gram‐negative Klebsiella pneumoniae. Ag(I) alginates suppressed 99.95% of bacterial growth in vitro. Even after four soak‐and‐dry cycles in deionized water Ag(I)‐CM‐cotton printcloth suppressed 99.99% of bacterial growth in vitro. Published in 2007 by John Wiley & Sons, Ltd.     

Thermogravimetry of deposited caustic soda used as a flame-retardant for cotton fabric

We have investigated the effect of caustic soda as a nondurable finish on the flammability of 100% cotton fabric (plain 180 g m^?2). On the contrary to the mercerization, during the impregnation process, no tension was applied. In order to attain the alkali cellulose onto the fabric, the subsequent neutralization was not followed. Each bunches of fabrics were dipped into individual aqueous solutions of sodium hydroxide, followed by means of squeeze rolls and drying at 110°C. After conditioning nightlong, by using our ‘vertical flame test’ the optimum add-on values to impart flame-retardancy into cotton fabric was determined as 1.3 g sodium hydroxide per 100 g fabric. Thermogravimetry and derivative thermogravimetry (TG/DTG) of pure cotton, treated cotton with sodium hydroxide at its optimum efficiency to impart flame-retardancy into the fabric was fulfilled and the obtained curves were compared and commented. The effectiveness of this hydroxide is attributed to the heat dissipation by the remaining material in the consumed ash. The results obtained are in favour of ‘dust or wall effect theory’ and also gas dilution theory.     

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.     

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.     

Thermoanalytical studies of flame-retardant polyester/ cotton textile blends: a comparison of THPC-urea-PVBr and THPOH ammonia treatments

Flame-retardant polyester/cotton fabrics are increasing in importance in the apparel and household fabrics market. Phosphorus-nitrogen flame-retardant systems developed for 100% cotton are not necessarily effective for polyester/cotton blends. Bromine effectively imparts flame-retardant properties of polyester resins. It has been theorized that systems containing both bromine and phosphorus should be suitable for polyester/cotton blends. A thermoanalytical study was undertaken to elucidate the effect of bromine in flame-retardant polyester/cotton blend fabrics. Fabrics having various ratios of polyester to cotton were treated with THPOH---NH₃, which is particularly effective on 100% cotton, and with THPC-urea-PVBr, which was designed for 50/50 polyester/cotton blends. For comparison, data are also presented on a 50/50 polyester blend fabric treated with THPOH---NH₃ and with THPC—urea flame retardants plus tris(2,3-dibromopropyl) phosphate in a two-step application. TG and DSC data were obtained in atmospheres of either nitrogen or air, using a DuPont 990 Thermal Analysis System². The thermal changes are assigned to decompositions of cotton, polyester, char, and resin finish. A comparison is made of the effects caused by the different flame-retardant finishes. Ol values and FF 3-71 data are reported.     

Thermogravimetric analysis of polyester/cotton blends treated with Thpc-urea-poly(vinyl bromide)

Polyester/cotton fabric swith blend ratios of 0/100, 11/89, 20/80, 30/70, 50/50, and 65/35 were investigated via thermogravimetric analysis in both nitrogen and air atmospheres. The samples were heated from ambient to 750°C at a heating rate of 5°C min^?1. The same fabrics were analyzed after treatment with tetrakis (hydroxymethyl) phosphonium chloride-urea-poly(vinyl bromide) (Thpc-urea-PVBr) flame retardant.Weight losses observed during pyrolysis were assigned to the cotton and polyester portions of the blends. Both cotton and polyester thermally decompose to yield gases and solid char byproducts. In nitrogen the 100% cotton fabric undergoes one major weight loss between 270 and 370°C, with the maximum rate of weight loss, 0.15 mg/min-mg occurring at 346°C. Thermal decomposition of the 100% polyester occurs over a range of 335–470°C, with the peak rate of weight loss, 0.11 mg/min-mg, measured at 416°C. In an air atmosphere, both volatile gases and solid char by- products of pyrolysis undergo combustion. The combustion reactions are associated with measured weight losses. The maximum rate of weight loss for the cotton portion increases to 0.25 mg/min-mg and occurs at 317°C. The maximum rate of polyester decomposition remains the same in both air and nitrogen, but the temperature decreases to 405°C.     

Enhanced thermal and combustion resistance of cotton linked to natural inorganic salt components

A comparison of the thermal decomposition and combustion characteristics of raw and scoured cottons has demonstrated a mechanistic link caused by the presence of inorganic salts in raw cotton, which enhances resistance to heat and flame. Thermogravimetry, differential thermogravimetry, and microscale combustion calorimetry were used to examine the thermal decomposition kinetics and thermal stability of cotton. During pyrolysis, both raw cotton nonwoven and woven fabrics exhibited a slower decomposition with a larger initial weight loss and produced a greater char yield, as compared to the fabrics after scouring, which removes most inorganic components from cotton. The activation energy (E _a ) values, calculated using the Kissinger method, the Flynn–Wall–Ozawa method, and the modified Coats–Redfern method, were consistently determined to be smaller for raw cotton than for scoured cotton. The analyses of cotton fabrics heated at elevated temperatures by ¹³C CP/MAS NMR and ATR-FTIR showed that trace quantities of inorganic components promoted the formations of oxygenated moieties at low temperatures and aliphatic intermediate char. In the combustion, raw cotton exhibited a much smaller heat release capacity and a smaller total heat release than scoured cotton, indicating enhanced thermal stability when the inorganic components are intact.     

Synthesis of gold nanoparticles using herbal Acorus calamus rhizome extract and coating on cotton fabric for antibacterial and UV blocking applications

Gold nanoparticles (AuNPs) have been synthesized by greener method using chloroauric acid as precursor and extract of Acorus calamus rhizome as reducing agent. Formation of AuNP was confirmed by the presence of Surface Plasmon Resonance (SPR) peak in UV–Visible spectral analysis. XRD and FT-IR spectral analyses were performed for characterization. SEM images show spherical morphology and HR-TEM images reveal nanosize of AuNPs. The AuNPs were then coated on cotton fabric by pad-dry-cure method and characterized by SEM with EDAX technique. The results reveal the deposition of AuNPs on the surface of cotton fabric. Uncoated cotton, neat extract coated cotton and extract containing AuNPs coated cotton fabrics were then tested for antibacterial activity against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacterial strains by AATCC 100 test method. It showed that the extract containing AuNPs coated cotton fabric had higher antibacterial activity than other test samples against E. coli. UV-DRS analysis performed on extract containing AuNPs coated cotton fabric showed improved UV-blocking property than uncoated cotton fabric and neat extract coated cotton fabric.