Graphene coated cotton nonwoven for electroconductive and UV protection applications

The functional properties and applications of graphene coated textiles depend on the magnitude of graphene add-on which in turn is influenced by the type of substrate and the dipping conditions. In the present study, optimized GO (graphene oxide) dipping conditions are identified for the preparation of cost-effective and scalable rGO (reduced graphene oxide) coated cotton nonwoven for electroconductive and UV (ultraviolet) blocking applications. To understand the influence of GO dipping variables on rGO add-on and electrical resistivity of cotton, batch adsorption studies are carried out in loose fibre form to eliminate the structural influence of yarn or fabric. Batch adsorption studies suggest that GO concentration, pH of GO solution and sodium dithionite (reductant) concentration are the most influencing dipping variables and these dipping variables are optimized for cotton nonwoven fabric using Box–Behnken response surface design to achieve minimum surface resistivity. The rGO coated cotton nonwoven fabric shows excellent UV blocking properties (UV protection factor = 89.38) at the optimized GO dipping conditions. Physical properties of cotton nonwoven fabric such as GSM, thickness, stiffness, breaking strength and elongation are analysed at different dipping cycles. After the rGO coating, bending rigidity, bending modulus and breaking elongation of the cotton nonwoven fabric decrease, whereas the breaking strength increases. rGO coated cotton fabric exhibits excellent stability towards multiple washing and rubbing. The graphene coated cotton is characterised by FT-IR, XRD, Raman, TGA, FESEM and LEICA image analyser.

Scalable Sulfonate-Coated Cotton Fibers as Facile Recyclable and Biodegradable Adsorbents for Highly Efficient Removal of Cationic Dyes

Adsorbents with superior adsorption capacity and facile recyclability are viewed as promising materials for dye wastewater treatment. In this work, a novel sulfonate decorated cotton fiber as a biodegradable and recyclable adsorbent was fabricated for highly efficient removal of cationic dyes. Herein, the poly(sodium p-styrenesulfonate-co-N-methylol acrylamide) (P(SSNa-co-NMAM)) with SSNa units as adsorption sites and NMAM units as thermal-crosslinking points was synthesized for modification of cotton fibers in a large scale at high temperature (160 oC). The various characterization investigations confirmed the successful construction of the P(SSNa-co-NMAM) coated cotton fibers (PCF). As expected, the as-obtained adsorbent presented outstanding adsorption performance toward cationic dyes in the both static and dynamic states, even in the synthetic effluent. The adsorption processes of cationic dyes onto the PCF were well fitted by the Langmuir isotherm model and Pseudo-second-order kinetics, respectively. The thermodynamics study showed that the adsorption reaction of the cationic dyes onto PCF was a spontaneous and endothermic process. The maximum adsorption capacities of PCF toward MEB, RhB and MG were 3976.10, 2879.80 and 3071.55 mg/g, respectively. The responsible adsorption of dyes ontothe PCF was electrostatic interaction. Moreover, the adsorption capacity of PCF toward cationic dyes was slight influenced by pH value of solution, because of the stable feature of sulfonate moiety in acid and alkali. In addition, the as-prepared PCF exhibited satisfactory recyclability and reusability. Given the aforementioned results, the as-obtained PCF is a promising adsorbent with great potential for practical application in the dye-contaminated wastewater remediation.

Andrographis paniculata absorbed ZnO nanofibers as a potential antimicrobial agent for biomedical applications

The present study focuses on developing antimicrobial nanofibers with superhydrophobicity and insect repellent properties for wound dressing and biomedical applications. For the first time, Andrographis paniculata leaf extract was prepared and incorporated into ZnO nanofibers (AP-ZnO). The antifungal and antibacterial activities of AP-ZnO were tested using the agar plate method. Amid the bacteria and fungus strain tested, the prepared sample exhibited a greater efficiency against Staphylococcus aureus and Trichophyton rubrum respectively. AP-ZnO showed the highest larvicidal activity (100 ± 0.2) against Aedes aegypti, proving its insect repellent characteristics. The in vivo toxicity studies of AP-ZnO (100 μg ml−1) tested on Danio rerio ensure the biocompatibility of the prepared sample with maximum toxicity of 21.1% after 72 h, which is lower than commercial Prallethrin. Moreover, AP-ZnO-chitosan coated cotton fabric showed higher durability with contact angle (θ ∼ 151°) and was suggested to be used for self-cleaning applications in the biomedical sector. The examined results confirmed that AP-ZnO possesses different medicinal characteristics suitable for biomedical and pharmaceutical applications.

Effect of Sepiolite-Loaded Fe2O3 on Flame Retardancy of Waterborne Polyurethane

In this study, a kind of inorganic composite flame retardant (Sep@Fe2O3) was prepared by combining solution deposition and calcination methods using sepiolite microfiber material as carrier. This inorganic compound flame retardant was combined with waterborne polyurethane (WPU) through layer-by-layer method to prepare WPU composites. The SEM and EDS, TEM, and XRD were used to characterize the microscopic morphology and crystal structure of WPU composites. Thermogravimetric analysis tests confirmed the good thermal stability of WPU/Sep@Fe2O3 composites; at the temperature of 600°C, the carbon residual percentage of WPU/Sep, WPU/Fe2O3, and WPU/Sep@Fe2O3 composites is 7.3%, 12.2%, and 13.4%, respectively, higher than that of WPU (1.4%). Vertical combustion tests proved better flame-retardant property of WPU/Sep@Fe2O3 composite-coated cotton than noncoated cotton. The microcalorimeter test proved that the PHRR of WPU/Sep@Fe2O3 composites decreased by 61% compared with that of WPU. In addition, after combining with Sep@Fe2O3, the breaking strength of WPU increased by 35%.

Statistical Study of Nonthermal Plasma-Assisted ZnO Coating of Cotton Fabric through Ultrasonic-Assisted Green Synthesis for Improved Self-Cleaning and Antimicrobial Properties

Nonthermal plasma processing is a dry, environment-friendly and chemical-free method of improving the wettability, adhesion, self-cleaning and dying quality of fabrics without affecting their bulk properties. This study presents a green synthesis and coating method for the immobilization of nanoparticles of ZnO on the nonthermal plasma functionalized cotton fabric. The self-cleaning activity of ZnO-coated cotton was then optimized statistically. The ultraviolet protection and antimicrobial activity of the optimized and a control sample were also elaborated in this study. Psidium guajava Linn (guava) plant extract and zinc chloride were used in the ultrasonic biosynthesis of ZnO nanoparticles and concurrent immobilization over plasma functionalized cotton. Sodium hydroxide was used as a reaction accelerator. Statistical complete composite design (CCD) based on the amount of ZnCl2, NaOH and plasma exposure time was used to optimize the role of input parameters on the self-cleaning ability of the coated cotton. Methylene blue in water was used as a sample pollutant in the self-cleaning study. The ZnO-coated cotton showed notably high self-cleaning activity of 94% and a UV protection factor of 69.87. The antimicrobial activity against E. Coli and S. Aureus bacteria was also appreciably high compared to the control.

Recyclable Ag/TiO2@PDMS Coated Cotton Fabric with Visible-Light Photocatalytic for Efficient Water Purification

Multifunctional materials for water purification have attracted great attention due to the increased water pollution problems. However, fabricating the low-cost and recyclable separation material is still a challenge. Herein, we developed an Ag/TiO2@PDMS coated cotton fabric with self-clean ability, high flux, superior visible-light photocatalysts ability, and recyclability via the “powder + glue” strategy. The composites exhibit superhydrophobic (water contact angle 157°), and high separation efficiency. The separation efficiency of 20 times of repeated use remains 16322 Lm−2h−1 and the degradation rate of methylene blue (MB) remains almost no change. The high oil purification, catalytic property, excellent stability in harsh condition and recyclability enables the material as a satisfactory candidate for water purification.