Anti-microbial and methylene blue dye adsorption properties of cotton fabrics modified with TiO2, Fe, Ag-doped TiO2, and graphene oxide nanomaterials

Nanoparticle materials have received increasing attention in the functional modification of textiles. In this work, pure TiO2, Ag-doped TiO2, Fe-doped TiO2, and graphene oxide nanoparticles were used to impart the anti-bacterial and adsorptive properties of nanoparticles to cotton fabric. The treated fabric materials were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The obtained treated fabrics were used as adsorbents for the removal of methylene blue from aqueous solution. The functionalized cotton fabrics were tested for their anti-microbial capability against Escherichia coli, Bacillus cereus, and Candida albicans. All the functionalized fabrics have higher anti-microbial activity compared to untreated cotton, especially the fabrics containing silver and Fe-doped TiO2. The optimum conditions of the adsorption process are determined via the study of the effect of the initial concentration of dye, pH, and contact time on the removal efficiency. Langmuir, Freundlich, and Temkin isotherms are applied for the equilibrium adsorption data. GO-Cot and Ag-Ti@GO-Cot samples showed the highest adsorption removal activity. The linear correlation coefficient ( R2) showed that the Temkin model well fitted the data of adsorption in the GO-Cot sample. The analysis of experimental data with different kinetic models showed that the pseudo-second-order kinetic model well fitted the adsorption data better than the other kinetic models of the pseudo-first-order, Elovich, and intra-particle diffusion.

The Thermo-Oxidative Behavior of Cotton Coated with an Intumescent Flame Retardant Glycine-Derived Polyamidoamine: A Multi-Technique Study

Linear polyamidoamines (PAAs) derived from the polyaddition of natural α-amino acids and N,N′-methylene bis(acrylamide) are intumescent flame retardants for cotton. Among them, the glycine-derived M-GLY extinguished the flame in horizontal flame spread tests at 4% by weight add-on. This paper reports on an extensive study aimed at understanding the molecular-level transformations of M-GLY-treated cotton upon heating in air at 300 °C, 350 °C and 420 °C. Thermogravimetric analysis (TGA) identified different thermal-oxidative decomposition stages and, coupled to Fourier transform infrared spectroscopy, allowed the volatile species released upon heating to be determined, revealing differences in the decomposition pattern of treated and untreated cotton. XPS analysis of the char residues of M-GLY-treated cotton revealed the formation of aromatic nanographitic char at lower temperature with respect to untreated cotton. Raman spectroscopy of the char residues provided indications on the degree of graphitization of treated and untreated cotton at the three reference temperatures. Solid state 13C nuclear magnetic resonance spectroscopy (NMR) provided information on the char structure as a function of the treatment temperature, clearly indicating that M-GLY favors the carbonization of cotton with the formation of more highly condensed aromatic structures.

Environmentally Benign Phytic Acid-Based Nanocoating for Multifunctional Flame-Retardant/Antibacterial Cotton

Environmentally benign layer-by-layer (LbL) deposition was used to obtain flame-retardant and antimicrobial cotton. Cotton was coated with 8, 10, and 12 phytic acid (PA) and chitosan (CH)-urea bilayers (BL) and then immersed into copper (II) sulfate (CuSO4) solution. Our findings were that 12 BL of PA/CH-urea + Cu2+ were able to stop flame on cotton during vertical flammability testing (VFT) with a limiting oxygen index (LOI) value of 26%. Microscale combustion calorimeter (MCC) data showed a reduction of peak heat release rates (pHRR) of more than 61%, while the reduction of total heat release (THR) was more than 54%, relative to untreated cotton. TG-IR analysis of 12 BL-treated cotton showed the release of water, methane, carbon dioxide, carbon monoxide, and aldehydes, while by adding Cu2+ ions, the treated cotton produces a lower amount of methane. Treated cotton also showed no levoglucosan. The intumescent behavior of the treatment was indicated by the bubbled structure of the post-burn char. Antibacterial testing showed a 100% reduction of Klebsiella pneumoniae and Staphylococcus aureus. In this study, cotton was successfully functionalized with a multifunctional ecologically benign flame-retardant and antibacterial nanocoating, by means of LbL deposition.

Synthesis of Zinc Oxide Nanoparticles by Hydrothermal Methods and Spectroscopic Investigation of Ultraviolet Radiation Protective Properties

Ultraviolet radiation causes damages to the human body, such as skin ageing, skin cancer, and allergies throughout the world. Applying zinc oxide nanoparticles (ZnO NPs) in sunscreen products (like cloths or textiles) to protect human skin by absorbing the ultraviolet radiations that emerged from the sun. The main aim of this study is to investigate both absorbance and transmittance characteristics of the untreated and treated cotton textiles. For ZnO NPs using hydrothermal methods, they were made from Zn(NO3)2·6H2O and NaOH at a constant annealing temperature of 300°C. Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-vis spectroscopy were used to analyze the produced ZnO NPs. From the FT-IR result, ZnO NPs were observed in the region of 400-600 cm-1. Wurtzite hexagonal structure of ZnO NPs with the average crystal size 32 ± 49 nm was observed from XRD results. Flowers in the shape of synthesized ZnO NPs were observed from SEM images. The UV-vis penetration peaks were identified at 264 nm and 376 nm, with energy band gaps of 4.68 and 3.536 eV, respectively. When compared to bulk ZnO, the energy band gap of ZnO NPs was blue-shifted due to the impact of quantum confinement. The peaks in UV-vis absorption were caused by an electronic transition from the valiancy to the conduction bands. The high energy band shows high absorbance of the synthesis sample in the case of 264 nm. The ZnO NPs were manufactured and applied to 100% of raw cotton to impart sunscreen action to both untreated and treated cotton fabrics. The performance of treatment has been evaluated utilizing UV-vis spectroscopy through quantifying ultraviolet protective factors (UPF) and percentage of transmitted (%T) radiations. The treated cotton textiles have 61.50% UPF while 2.65% ultraviolet radiations were transmitted. In other words, untreated cotton textiles have 1.63% UPF while 74.56% ultraviolet radiation was transmitted. Therefore, the treated cotton textiles have excellent protection categories when compared to untreated cotton textiles.

Enhancing digital ink-jet printing patterns quality through controlling the crystallinity of cotton fibers

Cotton fibers have a high crystallinity, which makes a large number of reactive hydroxyl groups blocked and therefore affects the ink-jet printing performance of reactive dyes on cotton fabrics. In this work, the alkali treatment was employed to adjust the structure of cotton fibers. The crystallinity of treated cotton fibers reduced from 73.9–58.5%, and the breaking strength did not decrease compared with original cotton fiber. Thus, the accessible reactive hydroxyl groups and the wettability were enhanced for treated cotton fibers, which promoted the penetration of inks into the fibers. The optimal K/S value of 23.47 was achieved for treated cotton fabrics which was higher than that of untreated cotton fabrics (17.15). Meanwhile, the printed fabrics displayed good washing fastness, rubbing fastness and glossiness. This work provides an effective way for improving the utilization of dye solution and producing high-quality cotton fabric digital printing products.

Comparison of Various Properties Between Nanoencapsulated Cotton Denimfabricand The Untreated Cotton Denim Fabric

Examining electron magnifying instrument investigation was done to quantify the size of Nano cases. The molecule size assumes an essential part in deciding their bond to the texture. It is sensible to expect that the biggest particles will be effectively eliminate from the fiber surface, while the little particles will enter further and follow firmly into texture. The SEM examination of the treated textures showed Nano particles installed on to the textures. The method has been developed to prepare Nano encapsulation finish on100% cotton denim fabrics to impart functional properties. The Nano encapsulated cotton denim fabric is found to have the antimicrobial property even after 30 industrial washes. It likewise plainly exhibited that the treated textures showed expanded antibacterial and antifungal impact in correlation with the untreated texture utilizing utilitarian, physical, mechanical, solace and permeableness tests.

Modification of cotton fabrics with 2-diethylaminoethyl chloride for salt-free dyeing with anionic dyes

A chemical modification of cotton fabrics by 2-diethylaminoethyl chloride (DEAE-Cl) was achieved, and the resulted cotton fabrics demonstrated salt-free dyeing properties with anionic dyes. Nucleophilic property of hydroxyl groups in cotton cellulose was enhanced under alkaline conditions and could react with DEAE-Cl, a chemical possessing both nucleophilic and electrophilic sites. The monolayered DEAE-grafted cotton cellulose could further react with DEAE-Cl to form multiple cationic quaternary ammonium salts (denoted as DEAE@Cotton), which are highly interactive with anionic dye molecules. The strong electrostatic interactions between the DEAE@Cotton and the dyes eliminated the use of inorganic salts in cotton dyeing process. The chemical structure and property of DEAE@Cotton were characterized and compared with untreated cotton. The DEAE@Cotton can be dyed in a salt-free system, and the dye exhaustion was faster than the conventional dyeing method due to the robust electrostatic interactions of the fabrics with anionic dyes. The dyed fabrics demonstrated outstanding color fastness under repeated washing, light exposure, and crocking. The dye adsorption process on DEAE@Cotton follows Langmuir isotherm model (R2 = 0.9667). The mechanism of enhanced dyeability was experimentally proved by treating the fabric with other anionic dyes in a salt-free system, proving the process to be environmentally friendly and cost-effective. Graphic abstract

Electrical conductivity and mechanical properties of conductive cotton fabrics

Functional electrically conductive fabric with acceptable mechanical properties, which could be applied in electromagnetic shielding, was developed. Conductive cotton fabrics (cotton/PANI, cotton/Mn, cotton/Cu, and cotton/Co) were prepared by in situ chemical oxidative polymerization for (cotton/PANI) and pad dry curing method was used for nanometals application. The Nano size of the metals and polyaniline inclusion were proven through both Dynamic Liquid Scattering (DLS) and X-ray diffraction (XRD) which showed an increase in crystallite density in unit space and the nanoparticles ranged from 100–200 nm. The effect of gamma irradiation on different treated cotton fabrics was investigated. The mechanical properties against irradiation dose showed an improvement up to 40 kGy, for all treated fabrics. On the other hand, Young’s modulus for untreated cotton recorded the lowest value, while cotton/Co recorded the highest one. Moreover, both AC (Alternating Current) and DC (Direct current) conductivities values can be calculated. In DC conductivity cotton/PANI was found to be more conducive than the remainder of the treated fabric by surface metallization with transition metals; while in AC conductivity cotton/Mn was found to be more conducive than the rest of the treated samples. The conductivity value increases by increasing the gamma irradiation dose for cotton/PANI fabric. Also, g-factor values can be estimated from ESR signals and vary from 0.009 up to 0.059 for conductive cotton fabrics; whilst cotton/Mn fabric has six hyperfine splittings, indicating that it is a paramagnetic element.

Environmentally-Benign Phytic Acid-Based Multilayer Coating for Flame Retardant Cotton

Chemically bleached cotton fabric was treated with phytic acid (PA), chitosan (CH) and urea by means of layer-by-layer (LbL) deposition to impart flame retardant (FR) behavior using only benign and renewable molecules. Samples were treated with 8, 10, 12 and 15 bilayers (BL) of anionic PA and cationic CH, with urea mixed into the aqueous CH solution. Flammability was evaluated by measuring limiting oxygen index (LOI) and through vertical flame testing. LOI values are comparable to those obtained with commercial flame-retardant finishes, and applying 10 or more bilayers renders cotton self-extinguishing and able to pass the vertical flame test. Microscale combustion calorimeter (MCC) measurements show the average reduction of peak heat release rate (pHRR) of all treated fabrics of ~61% and the reduction of total heat release (THR) of ~74%, in comparison to untreated cotton. Decomposition temperatures peaks (T1max) measured by thermogravimetric analyzer (TG) decreased by approximately 62 °C, while an average residue at 650 °C is ~21% for 10 and more bilayers. Images of post-burn char indicate that PA/CH-urea treatment is intumescent. The ability to deposit such a safe and effective FR treatment, with relatively few layers, makes LbL an alternative to current commercial treatments.

Contact/Release Coordinated Antibacterial Cotton Fabrics Coated with N-Halamine and Cationic Antibacterial Agent for Durable Bacteria-Killing Application

Coating a cationic antibacterial layer on the surface of cotton fabric is an effective strategy to provide it with excellent antibacterial properties and to protect humans from bacterial cross-infection. However, washing with anionic detergent will inactivate the cationic antibacterial coating. Although this problem can be solved by increasing the amount of cationic antibacterial coating, excessive cationic antibacterial coating reduces the drapability of cotton fabric and affects the comfort of wearing it. In this study, a coordinated antibacterial coating strategy based on quaternary ammonium salt and a halogenated amine compound was designed. The results show that the antibacterial effect of the modified cotton fabric was significantly improved. In addition, after mechanically washing the fabric 50 times in the presence of anionic detergent, the antibacterial effect against Staphylococcus aureus and Escherichia coli was still more than 95%. Furthermore, the softness of the obtained cotton fabric showed little change compared with the untreated cotton fabric. This easy-to-implement and cost-effective approach, combined with the cationic contact and the release effect of antibacterial agents, can endow cotton textiles with durable antibacterial properties and excellent wearability.