Untreated Cotton Research Articles

Enhancing Dyeability and Antibacterial Feature of Cotton Through Nano-chitosan Attachment

In this study, cotton fabrics were chemically attached with nano-chitosan using cyanuric chloride as an anchor in order to enhance its dyeability towards direct dyes and its bacterial resistance. Low molecular weight chitosans were synthesized by hydrolysing chitosan by nitrous acid. The molecular weight was assessed viscometrically. The particle size of chitosans was reduced by ionic gelation technique, and the sizes were measured using particle size analyser. The nano-sized particles were then attached to cotton which was reacted to cyanuric chloride earlier. FTIR spectra and scanning electron microphotographs of the samples were analysed. The treated and untreated cotton samples were dyed using three direct dyes. The dye absorption of the treated samples in the absence of salt was found to be much higher compared with the untreated samples dyed in the presence of salt and could also improve wash fastness. The treated cotton samples showed improved antimicrobial behaviour as evaluated by agar diffusion method. Attachment of nano-chitosan to cotton did not adversely affect the feel of the fabric as found in case of unmodified cotton.

Effect of substrate-to-inoculum ratio on anaerobic digestion of treated and untreated cotton textile waste

Anaerobic digestion is a promising technology for biogas recovery from cotton textile waste. However, limited studies have focused on anaerobic digestion of cotton textile waste. This study evaluated the effect of different SIRs of 0.5, 1.0, 1.5, and 2.0 using treated and untreated cotton substrate in a batch anaerobic digestion process under mesophilic condition for 15 days. The cotton textile waste was treated with 0.5 M Na2CO3 at 150 °C for 3 h. The highest methane yield of 366.76 mL/g VS, which is equivalent to anaerobic degradability of 89.67%, was observed from SIR of 0.5 for untreated substrate. However, for treated substrate, SIR of 1.0, 1.5, and 2.0 shows an increased methane yield and anaerobic degradability of more than 50% when compared to untreated substrate. Furthermore, for treated substrate, higher substrate loading of SIR 1.0 produced a comparable yield of 306.73 mL CH4/g VS, which is equivalent to anaerobic degradability of 75%. The Gompertz model fitted with the experimental data with R2 value of 0.96-0.99, which was an improvement over the first-order kinetic model.

Chemical Modification of Cotton Fabrics by a Bifunctional Cationic Polymer for Salt-Free Reactive Dyeing.

Cotton modification exhibited great potential in the fabric dyeing industry. A bifunctional cationic polymer with a moderate cationic degree and low molecular weight was achieved via free radical polymerization between dimethyl diallyl ammonium chloride and allyl glycidyl ether. Then, it was further utilized for the modification of cotton fabrics. The formation of the cationic polymer was identified using Fourier transform infrared and nuclear magnetic resonance spectroscopies. The structure and properties of both treated and untreated cotton were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy. The modified cotton fabrics could be salt-free dyed with reactive dyes at low temperatures. While obtaining satisfactory color fastness and leveling properties, the dyeability of the modified cotton was improved significantly compared with the conventional dyeing of native cotton. Besides, the prepared cationic polymer has good flocculating properties to avoid secondary pollution, suggesting high potential for achieving an economical and eco-friendly dyeing process.

Antibacterial Finishing of Cotton Fabric Using Stinging Nettle (Urtica dioica L.) Plant Leaf Extract

Natural organic fibers such as cotton, linen, and wool are readily attacked by microorganisms. Microbial growth on a textile fabric causes loss of strength and elongation, discoloration, and changes in appearance. The antibacterial finishing agents extracted from nettle plant leaf have been used to impart finish to the cotton fabric by using the Pad-Dry-Cure application method. The antibacterial activity of the finish was assessed quantitatively using the AATCC 100:2004 test method, and the antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria was measured. There was a 100 to 99.75 percent reduction in the count of test bacteria. Physical properties of treated and untreated cotton fabrics such as absorbency, fabric stiffness, air permeability, and strength were analyzed. To evaluate the laundering effect of stinging nettle leaf finished fabric, samples were subjected to laundry with 5, 10, 15, 20, 25, 30, 35, and 40 washing cycles using standard AATCC test method 61, and bacterial count of treated samples was tested. The results showed gradual decrease in antibacterial property, with a 100 to 44% reduction in the bacterial count for Staphylococcus aureus and a 100 to 30% reduction in the bacterial count for Escherichia coli. The results of this investigation suggested that nettle leaf, a low-cost abundant plant in Ethiopia, can be used for antibacterial activity in woven cotton fabric.

Phytic Acid and Biochar: An Effective All Bio-Sourced Flame Retardant Formulation for Cotton Fabrics.

Flame retardant systems based on bio-sourced products combine quite high fire performances with the low environmental impact related to their synthesis and exploitation. In this context, this work describes a new all bio-sourced flame retardant system designed and applied to cotton fabrics. In particular, it consists of phytic acid (PA), a phosphorus-based naturally occurring molecule extracted from different plant tissues, in combination with biochar (BC), a carbon-rich solid product obtained from the thermo-chemical conversion of biomasses in an oxygen-limited environment. PA and BC were mixed together at a 1:1 weight ratio in an aqueous medium, and applied to cotton at different loadings. As revealed by flammability and forced combustion tests, this bio-sourced system was able to provide significant improvements in flame retardance of cotton, even limiting the final dry add-on on the treated fabrics at 8 wt.% only. The so-treated fabrics were capable to achieve self-extinction in both horizontal and vertical flame spread tests; besides, they did not ignite under the exposure to 35 kW/m2 irradiative heat flux. Conversely, the proposed flame retardant treatment did not show a high washing fastness, though the washed flame retarded fabrics still exhibited a better flame retardant behavior than untreated cotton.

Influence of Potassium Permanganate Oxidation on Structure and Properties of Cotton

ABSTRACT Cotton yarn was oxidized using the various concentrations and pH of potassium permanganate solutions, in order to investigate the influence of oxidation parameters on chemical, mechanical and sorption properties of cotton. The oxidation progress was monitored through weight loss, carbonyl and carboxyl group content, tensile strength, moisture sorption, crystallinity change, surface charge and morphology of modified samples. The carboxyl groups were introduced into the oxidized cotton up to 0.3 mmol·g−1, while the weight loss was up to 5%. The oxidized samples, compared with untreated cotton, exhibited lower tensile strength, higher moisture sorption and surface roughness. Surface charge was evaluated through measurement of zeta potential at different pH of electrolyte, and the correlation was established between carboxyl group content and zeta values measured at neutral pH, which proved that zeta potential can be a valuable tool for characterizing changes in the structure of oxidized cellulose textile materials.

Utilizing some synthesized nanostructured materials to improve the functional properties of cotton fabric for possible applications

The potential of the synthesized Copper Oxide (CuO)and Graphene Oxide (GO)nanostructures as an efficient modifier for cotton fabric surface, to enhance its functional properties when dyed with C.I. Reactive Yellow 160 (RY 160) was investigated. For this purpose, Copper Oxide nanoparticles (CuO NPs) and Graphene Oxide nanoparticles (GO NPs) were synthesized and characterized through SEM, and EDX analysis, TEM analysis, FTIR spectrum analysis and X-ray diffraction (XRD) analysis. The cotton fabric was first treated separately with CuO NPs and GO NPs, and then dyed with RY160. The dye exhaustion percentages (E%) of pretreated cotton fabric samples were compared with their corresponding values obtained through conventional dyeing of untreated cotton. Dye adsorption rate constants according to pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models were calculated. Moreover, the diffusion coefficients and the activation energy of diffusion of RY160 into cotton fabrics were calculated before and after NPs treatment. The activation energy of diffusion of RY160 into pretreated GO NPs-cotton fabric was the lowest value, saving 44.06% of the energy required for conventional dyeing completion. The overall adsorption process follows pseudo-second order kinetics and intraparticle diffusion model. The corresponding thermodynamic parameters, namely enthalpy (∆ H), entropy (∆ S ), and free energy changes (∆ G ), were also calculated for untreated cotton fabric and compared with the data obtained for treated cotton fabrics after surface modification via synthesized nanomaterials, CuO NPs and GO NPs. The NPs treatment produces a cotton fabric with advanced color fastness and antibacterial properties enabling them to improve human health care and decrease the environmental impacts and fabric damage.

Preparation and characterization of flame retardant cotton fabrics

An inorganic flame retardant glass was prepared using the melt methods. The prepared glass was characterized using IR, X-ray. The x-ray patterns and IR charts show that the formation of glass without any crystals. Cotton fabric was finished using different percentage of glass 0.5, 1, 1.5 and 2 % (w/w) in the presence of citric acid as crosslinker and sodium hypophosphite as catalyst. The flame retardancy of finished cotton fabric was performed using Limited Oxygen Index (LOI) technique. The results of measurements show that the value of LOI of untreated cotton fabric equals 19.6, when cotton fabrics treated with different amounts of glass ranging from 0.5 to 2 %, the value of LOI increased to become 23.6 at 0.5% and 24.8 for the higher glass concentration. The effect of curing temperature and time on the properties and the LOI of cotton fabric was studied.

Multifunctional flame-retarded and hydrophobic cotton fabrics modified with a cyclic phosphorus/polysiloxane copolymer

A novel cyclic-shaped copolymer containing silicon and phosphorus, poly (tetramethylcyclosiloxyl spirocyclic pentaerythritol diphosphonate) (PCTSi) was successfully synthesized and characterized by Fourier transform infrared spectra (FT-IR), 1H and 13C nuclear magnetic resonance (1H NMR and 13C NMR) for the preparation of flame retardant and hydrophobic cotton fabrics. The surface morphology of treated cotton fabrics was characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The thermal degradation and combustion properties of cotton fabrics before and after treatment were investigated by thermogravimetric (TG) analysis, limiting oxygen index (LOI) test, vertical burning test and cone calorimetry test. After treated with PCTSi, the LOI value of coton fabrics increased to 29.5%, which was significantly higher than untreated cotton fabrics and the LOI value remained at above of 26.0% after 20 washing times. In the vertical burning test, the PCTSi treated cotton fabrics showed no afterflame and afterglow with a minimum char length of 8.5 cm. Thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) results indicated that flame-retardant cotton fabrics released nonflammable gases and less flammable gases than the untreated cotton fabrics. X-ray diffraction analysis demonstrated that the crystal structures of the PCTSi-treated cotton were almost unaffected. According to the results of TG-FTIR, SEM, EDS, and analyses of char residues, the cyclic-shaped copolymer can significantly improve flame retardant performance of cotton fabric by promoting the generation of char layer and the release of noncombustible volatiles. The treated cotton fabrics showed excellent hydrophobic properties, which reached a contact angle (CA) of 150° compared with cotton fabrics without treatment. In addition, 119.18° of CA and 26.0% of LOI value can be maintained after 20 washing times.

Green synthesis of copper oxide nanoparticles: a promising approach in the development of antibacterial textiles

Textiles are known to be the best substrates for growing a variety of microorganisms efficiently at appropriate temperatures and humidity in contact with the human body. Currently, increasing public concern about hygiene has been driving many investigations about antimicrobial surface modification of textiles. The present research reports on the synthesis and characterization of nanosized copper oxide nanoparticles (CuONPs) and their application on cotton fabric to increase the bactericidal and hydrophobic properties. The synthesized materials have been subjected to spectroscopic and microscopic characterizations to help in understanding their structure, morphology, size, and composition. Further, upon dispersion of the nanoparticles onto the fabric, its hydrophobicity and mechanical properties were evaluated using electron microscopy and universal testing machine. Treated cotton fabric exhibits higher tensile strength (32 MPa) than the untreated one (27 MPa), whereas copper nanoparticle-coated cotton fabric shows a fair hydrophobicity. Moreover, CuONPs-treated and untreated cotton fabrics have been analyzed for bactericidal activity against various gram-negative and gram-positive strains. Finally, the CuONPs-coated cotton fabric displays greater antibacterial activity against E. coli and exhibits superior antimicrobial activity even after 30 cycles of washing, indicating that the CuONPs-coated cotton fabric has a higher potential to be employed as a medical textile to avoid cross-infection within a clinical environment.

Flame-retardant and water-repellent coating on cotton fabric by titania–boron sol–gel method

This work aims to prepare a series of sols based on Titanium (IV) butoxide (TBT) and using boric acid as a functional additive. The sols were applied onto the cotton fabric by the pad-pry-cure process. The as-obtained cotton fabrics were characterized using Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) analysis in order to determine their chemical composition and their surface morphology, respectively. The results indicate the formation of TiO2–boron-based coating over the surface of coated cotton fabric. X-ray diffraction (XRD) patterns showed that the coating did not affect the crystallographic structure of the cellulosic fabric. The functional properties of the treated samples were measured from thermo-oxidative stability and burning behavior performance, drop absorption and water uptake measurements. The results showed that the coated cotton fabrics by the sol–gel approach through the application of TiO2–boron-based coating with 2.5 molar ratio of boric acid possessed high thermal stability and flame retardancy. Most importantly, a total burning time of 2 s and a residue of more than 90% were obtained after 10 s of flame application, indicating that the functionalized cotton fabric self-extinguished the fire rapidly. The water-repellent properties were also enhanced and the obtained results mentioned that the drop time and the water uptake were improved compared with untreated cotton fabric. The effect of the application of TiO2–boron-based coatings on the mechanical properties of cotton samples, as well as their washing fastness were studied.

Nano technology applications in textile to improve puncture resistant of fabrics

Nanotechnology is an evolving technology, resulting in significant differences in product behavior. Applications of Nano materials in textiles are constantly growing to improve performance and create unparalleled textile functions for their enormous technical, economic and ecological advantages. It is expected that Nano materials will either enhance existing properties or add new functionalities to textiles such as dirt and water repellent, breathability, UV protection, conductive and anti-static properties, wear and wrinkle resistance or stain resistance or bacteria. Due to advancement in manufacturing of Nano materials, a new developed materials specified in the area of protection has been discovered such as; carbon Nano tube (CNT) and Graphene. CNT has unique mechanical properties, particularly in improving tensile strength, and is one of the strongest known materials used in high-performance nanocomposites due to their unique mechanical properties. And its properties make it the best to reinforce polymers and have a great potential for use in the manufacture of ballistic-resistant materials. Graphene is an allotrope of carbon that exists as a two dimensional sheet. graphene is as a single layer of graphite, where all the carbons exist in a regular hexagonal array, it’s the first two dimensional materials to be available. It is both the lightest known substance and the strongest ever produced. The ability to be solid, strong and flexible at the same time gives this incredible potential for use as a body armor or shielding. Research Subject: Insufficiency of puncture resistant Nano treated fabrics in the Egypt. Objective: Develop and improve puncture resistant factor for cotton fabrics using Nano technology in Egypt. Methodology: Experimental method. Results: The most important results are Emphasize the effective role of Nano technology in puncture resistant in textiles. Through Nano technology and Nano additives a wide range of properties could be added to fabrics. The impact proof treatments of fabrics and material developments have several applications. The mechanical properties of textile fibers can be enhanced by incorporation of nanoparticles in fiber, such properties include increasing puncture resistant. Hematite (Iron III Oxide) Nanoparticles were applied to cotton fabrics using polyurethane cold cure foams as a binder, the treatment enhanced the mechanical properties ‘puncture resistant’, The experiment shows a significant increase in puncture resistance for treated fabrics. Effect of Nano iron on physical properties of cotton fabric lead to Changes in physical properties of Nano iron loaded cotton fabric was evaluated in terms of puncture resistance and compared with the untreated cotton fabric.

Development of Flame-Resistant Cotton Fabrics with Casein Using Pad-dry-cure and Supercritical Fluids Methods

Traditional pad-dry-cure (PDC) and supercritical carbon dioxide (scCO2) methods were used to study the effectiveness of cotton fabrics treated with casein from bovine milk and eco-friendly inorganic materials, urea and diammonium phosphate. Trials were completed successfully. Thermogravimetric analysis (TGA), microscale combustion calorimeter (MCC), 45° angle and vertical flammability (clothing textiles test) and limiting oxygen index (LOI) tests were carried out for the treated cotton fabrics. When the treated fabrics were tested using the 45° angle flame, the ignited fabrics self-extinguished and left behind a streak of char. Treated higher add-on fabrics were neither consumed by flame, nor produced glowing embers upon self-extinguishing. All untreated cotton fabrics showed limiting oxygen index (LOI) values of about 18% oxygen in nitrogen. For formulations with casein, urea and diammonium phosphate, LOI values of treated fabrics were 29-40% oxygen in nitrogen when add-on values for the formulation were 9.5-18.7wt%. Furthermore, scanning electron microscope (SEM) was employed to characterize the chemical structure on the treated fabrics, as well as, the surface morphology of char areas of treated and untreated fabrics. The results indicate that fabrics treated with casein are flame resistant. The treated fabrics exhibited improved thermal stability, as evidenced by increased ignition times and lower heat release rates. The results of this study show that casein coated flame-resistant fabrics can be readily applied to textile fabrics using a continuous process that is ideal for commercial and industrial applications.

A novel, eco-friendly and durable flame-retardant cotton-based hyperbranched polyester derivative

A novel, formaldehyde-free, efficient and durable flame-retardant hyperbranched polyester derivative (HBPPN), containing nitrogen and phosphorus, was synthesized using a second-generation hyperbranched polyester, phosphorous acid and urea. The HBPPN was characterized by FT-IR and nuclear magnetic resonance spectroscopy. The FT-IR spectra indicated that the HBPPN may be grafted onto cotton by covalent bonds, modifying the degradation of the cotton. The flame-retardant properties of the HBPPN-treated cotton fabric were investigated based on vertical flammability, LOI, and cone calorimetry. The LOI value of 160 g/L HBPPN-treated cotton fabric was 39.6%, and the LOI value decreased to 27.3% after 50 laundering cycles, indicating the high durability of the cotton fabric treated with HBPPN. The vertical flammable tests showed that the cotton fabrics treated with HBPPN had short char lengths. The surface morphology of HBPPN-treated cotton fabrics was assessed using SEM. TGA demonstrated that the cotton fabrics treated with HBPPN easily formed char. Cone calorimetry indicated obviously lower values of PHRR and THR relative to those of the untreated cotton fabrics. XRD revealed that treatment with HBPPN did not substantially change the crystalline structure of the cotton. These results confirmed that HBPPN exhibited excellent flame retardancy and high durability.

Zinc Stannate Nanostructure: Is It a New Class of Material for Multifunctional Cotton Textiles?

This study demonstrates the synthesis of nano-zinc stannate and its application as a novel multifunctional finishing agent on cotton fabric. Nano-zinc stannate has been synthesized by the co-precipitation method, and the nanostructures produced have been characterized to investigate their morphology and microstructure by using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction techniques. The synthesized nano-zinc stannate has been applied on cotton fabric and the multifunctional efficacies of the treated fabric, like UV resistance, antibacterial property, self-cleaning, as well as thermal stability, were analyzed. The as-synthesized zinc stannate-treated cotton fabric showed excellent efficiency in self-cleaning, antibacterial property, and flame-resistant action compared to the annealed nano-zinc stannate-treated cotton fabric. It was observed that the ultraviolet protection factor of the treated (annealed zinc stannate-treated) fabric shoot up more than 45 after treatment, and the same fabric showed more than 90% bacterial resistance against both Gram-positive and Gram-negative bacteria. Concerning thermal kinetics, the as-synthesized zinc stannate-treated fabric registered a 39% reduction in the peak heat release rate compared to the untreated cotton fabric, and it also showed catalyzed pyrolysis action and more amount of char mass (30–40% more compared to the control cotton) formation at higher temperature. The self-cleaning efficacy of the treated fabric has been examined against coffee stain and basic methylene blue dye. The treated fabric exhibited a good efficiency in cleaning of stain due to the free-radical scavenging behavior. Finally, it also has been proved that the integration of these nanostructure did not have any detrimental effect on the important physical properties (tensile strength, flexibility, and crease resistance) of the treated fabric.

Design of functional cotton fabric via modified carbon nanotubes

PurposeOne of the intensively developed in recent years new materials are hybrid textiles modified with carbon nanotubes (CNT). In this paper, CNTs was modified by grafting dimethyl phosphite and perfluorohexyl iodine. It was applied to the cotton to obtain the flame-retardant, water-repellent, ultraviolet-resistant and conductive multifunctional fabric.Design/methodology/approachThe modified CNTs were loaded onto cotton fabric by impregnation and drying. The CNTs-multi was synthesized by grafted dimethyl phosphite and perfluorohexyl chain and applied to the cotton by dipping-drying method. The surface chemistry of functionalized CNTs was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The combustion properties were evaluated using a microscale combustion calorimeter, match test and TGA analysis. Surface hydrophilicity and hydrophobicity of fabric surface was characterized by static contact angle, and the UV resistance of the fabric was represented by the UPF value.FindingsDimethyl phosphite and perfluorohexyl chain were grafted on the surface of CNTs successively. The quantity of each component on the surface of CNTs was calculated according to XPS results. According to miniature combustion calorimeter data, both the value of maximum heat release rate (PHRR) and total heat release (THR) of CNTs -multi/cotton was about 65% lower than that of untreated cotton fabric. The residue after combustion of CNTs -multi/ cotton in the match test was more compact. The electrical conductivity of multi/ cotton is 225.6 kΩ/□, which is better than that of untreated cotton fabric. The UPF value of CNTs-multi/cotton reached 121, which was indicated that the anti-ultraviolet performance of CNTs-multi was greatly improved.Research limitations/implicationsModifying method to increase the functional component amuount on the CNTs surface still need to be explored, which could increase the hydrophobicity. How to further improve the functional effect and the general synthetic steps will be of great significance to the preparation of multifunctional modified cotton fabric.Practical implicationsThis modifying method can be used in any of multifunctional textile preparation process. The UV-resistant and flame retardant cotton fabric was revealed as a sample for use in outdoor sports such as clothes and tents.Originality/valueTo meet the needs of multifunctional cotton fabric, the modification of CNTs with dimethyl phosphite and perfluorohexyl iodine has not been reported. The modified fabric has flame-retardant, UV-resistant conductive and conductive properties.

Cotton fiber functionalized with 2D covalent organic frameworks for iodine capture

By using a rapid cryogenic reaction, cotton fiber was covalently functionalized with imine-linked two-dimensional covalent organic frameworks (2D COFs), which was synthesized via an imine condensation reaction between 1,3,5-tris(4-aminophenyl)benzene and terephthaldehyde. The resulting functionalized cotton (COFs@cotton) was characterized by fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscope, thermo-gravimetric analysis, nitrogen adsorption–desorption analysis and elemental analysis. The presence of a lot of imine functional groups in combination with dispersed mesoporous holes results in rapid adsorption rate and relatively high iodine affinity with uptake capacities up to 533.9 mg/g, which was much higher than that of untreated cotton. In addition, COFs@cotton also shows remarkable capability as absorbent for iodine in solution. The adsorbed iodine can be completely extracted from COFs@cotton by being washed with ethanol, permitting the simple reuse of adsorbent. This new functionalization approach can be applied to different kind of imine-linked COFs, and the corresponding adsorbents show more extensive practical application prospect for iodine capture.

FT-IR spectroscopy and morphological study of functionalized cellulosic fibers: Evaluation of their dyeing properties using biological Pistacia vera hulls by-product extract

The repulsion between cellulose and anionic entities could be overcome by imparting cationic sites on its structure. In this work, we studied the treatment of cotton fabric with different amounts of chitosan bio-polymer (0.0125–0.075%), dimethyl diallyl ammonium chloride and diallylamin co-polymer (1–5%), alum (0.5–20 g/L), and sodium chloride (2–40 g/L) in order to improve their dyeing behaviors with an ecological extract of Pistacia vera hulls by-products. The chemical modification of the cellulosic fibers was confirmed using Fourier Transform Infra-Red (FT-IR) and Scanning Electron Microscopy (SEM). The unmodified and modified cellulosic samples were, then, dyed with Pistacia vera extract. The dyeing characteristics were assessed through the measurements of the color coordinates and the color strength. Results showed that the dyeing performance followed the order: Cotton-dimethyl diallyl ammonium chloride and diallylamin co-polymer (K/S = 9.6) > Cotton-Chitosan (K/S = 8.97) > Cotton-Alum (8.84) > Cotton-NaCl (K/S = 6.06) > Untreated cotton (K/S = 1.98). All dyed samples exhibited good fastness to washing, rubbing and light. Overall, it has shown in this study that the functionalization of cellulose structure could greatly improve its dyeing behavior depending on the cationic sites number.

Synthesis and properties of cotton fabric functionalized by dimethyl phosphite and perfluorohexyl group grafted graphene oxide

Purpose Nanotechnology has been able to bind to a wide range of functional textiles in recently. This paper aims to modify graphene oxide (GO) by grafting dimethyl phosphite and perfluorohexyl iodine. It was applied to cotton to obtain a flame-retardant, water-repellent and ultraviolet-resistant multifunctional fabric. Design/methodology/approach The GO-multi was synthesized by grafted dimethyl phosphite and perfluorohexyl chain and applied to cotton by the dipping-drying method. The surface chemistry of functionalized GO was characterized by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The thermal stability of the fabric was characterized by thermogravimetric analysis (TGA). The combustion properties were evaluated using a microscale combustion calorimeter, match test and TGA. Hydrophobicity of film and fabric surface was characterized by static contact angle, and the UV resistance of the fabric was represented by the ultroviolet procetion factor (UPF) value. Findings Dimethyl phosphite and perfluorohexyl chains were grafted on the surface of GO successively. In the match test, the GO-multi/cotton kept the original outline of the fabric. According to the micro-scale combustion calorimetry (MCC) data, the value of PHRR and THR of GO-multi/cotton was about 45 per cent lower than that of untreated cotton fabric. It was found from the field-emission scanning electron microscopy (SEM) pictures that the residue of GO-multi/ cotton burned by the match method was more compact and the graphene lamellar structure remained more complete. The hydrophobic effect of GO-multi/cotton was improved compared to untreated cotton, but not better than the fabric treated by the perfluorohexyl chain-grafted GO. The UPF value of GO-multi/cotton reached 253, which indicated that the anti-ultraviolet performance of GO-multi was greatly improved after it was deposited on the cotton fabric. Research limitations/implications Although the hydrophobic effect was much higher than that of untreated cotton fabric, its hydrophobic effect was not satisfied, which may be due to the fact that the content of F element content was low. So, it is still needed to explore the modifying method to increase the functional component amount on the GO nanosheet. Practical implications This modifying method can be used in any of multifunctional textile preparation process. The hydrophobic and flame-retardant cotton fabric revealed a sample for use in outdoor sports such as clothes and tents. Originality/value To meet the needs of multifunctional cotton fabrics, the modification of GO with dimethyl phosphite and perfluorohexyl iodine has not been reported. The modified fabric has flame-retardant, UV-resistant and hydrophobic properties.

Internal validation of latest generation STR kits for direct STR typing from reference samples

Forensic STR kits are manufactured by various biotechnology companies. Differences in primer designs and proprietary chemicals, as well as the availability of instruments in each laboratory, may result in performance differences. As such, internal validation is a necessary step prior to adopting a new kit, especially if accreditation is sought. Here, we evaluated three latest generation direct STR kits (Thermo Fisher Scientific’s GlobalFiler® Express, Promega’s PowerPlex® Fusion 6C, and Qiagen’s Investigator® 24plex GO!) for direct STR typing of reference samples as part of ISO17025:2017 implementation. Thirty buccal swab samples (untreated cotton swabs) were used to optimize the parameters that could affect test results, such as the amount of swab used, PCR cycle number, and electrophoretic injection condition. Each kit was then used for direct STR typing of additional one hundred untreated buccal swabs. A scoring system based on profile quality was used to evaluate the kits: high-quality, minor-issue, moderate-issue, and critical-issue. GlobalFiler® Express kit showed the highest number of high-quality profiles (i.e. full profile with no quality flag), followed by PowerPlex® Fusion 6C and Investigator® 24plex GO!. Non-standard loci typed in the kits (e.g. DYS391 and “Quality Sensors”) provided additional information in cases where amelogenin-Y failed to amplify and also where inhibitors were present. In summary, we selected the GlobalFiler® Express kit for direct STR typing of untreated buccal swab samples due to its superior performance.