Application of zinc oxide nano particles using polymeric binders on cotton fabric

Purpose The durability of antimicrobial agents and its effectiveness is the most important factor for consumer usage. One important class of antimicrobial agents are inorganic metals and their metal oxides which can be prepared into nanoparticles and can be imparted to enhance the antimicrobial properties. The purpose of this paper is to investigate the effect of three different polymeric binders during the application of zinc oxide (ZnO) nanoparticles on the antimicrobial and performance properties of the finished fabric. Design/methodology/approach In this study, ZnO nanoparticles were prepared by a wet chemical method. The nano-particles size distributions was determined using Nanoplus Dynamic Light Scattering particle size distribution analyzer and concentration of nano ZnO 0.1% (w/v) was applied with 2% (w/v) polymeric binders, namely, polyvinyl alcohol (PVA), polyurethane (PU) and butyl acrylic (BA) on cotton fabric by pad dry cure method. The treated samples were tested for physical properties such as tearing strength, tensile strength, crease recovery and air permeability and antimicrobial properties using test method American Association of Textile Chemists and Colorists (AATCC) 100. Further, the content of zinc in the treated samples was determined by the atomic absorption method. The treated fabric was analyzed using fourier transform infrared spectroscopy and scanning electron microscopic and also tested for cytotoxicity as per International Organization for Standardization 10993. Findings The results indicated that the type of polymeric binders did not show any influence on the uptake of the zinc content. All treated samples showed positive results >99% with regard to antibacterial property. However, the polymeric treated samples showed a difference in physical properties. The ZnO nano-finish reduced the tensile strength and tearing strength of the fabrics. The difference in crease recovery for samples ZnO/PVA and ZnO/PU was not much except for ZnO/BA where it increased by 38%. The air permeability decreased after application for all treated samples, the lowest among treated samples was in ZnO/PU fabric. Further, ZnO/PVA finished fabric was found to retain antibacterial property up to 50 washes and was effective against MS2 Bacteriophage as a surrogate virus when analyzed as per AATCC 100–2012 test method, and therefore can be potentially used as health-care apparel such as doctors coat and scrub suits. Originality/value The outcome of this research is in its contribution to the field of reusable textiles. It highlights the use of nanotechnology to design and develop cotton fabrics for antimicrobial properties which has the potential of preventing the growth of harmful bacteria. The study brings forth the use of ZnO nanoparticles mixed with PVA binder on 100% cotton fabrics which exhibits antibacterial and antiviral properties with adequate wash durability. Currently, there is a high demand of effective durable textiles with barrier properties and the present study provides a promising solution to provide reusable textiles with a greater level of protection.

3D printing of Portland cement-containing bodies

Purpose Recent advances in 3D printing construction elements have focused on ordinary Portland cement (OPC) concrete using polymeric binders; herein, this study aims to produce the same using pure water. Design/methodology/approach A binder jet printer prototype was used to fabricate specimens that are used to assess geometric and mechanical properties. Two distinct water-based binder formulations, compatible with OPC chemistry and piezoelectric jetting device, were used: pure water and water-polyvinyl alcohol (98:2 w/w) solution. Findings This study examines the effect of binder flow rate on dimensional accuracy. Furthermore, the changes in the mechanical properties over time with hydration have been investigated. Practical implications Results indicate that the increase in mechanical strength of Portland cement concrete with pure water was consistent; however, it was delayed by the water: PVA (98:2 w/w) solution. Post-curing by water vapor hardened the structure with the removal of layering native to 3DP and decreased infilling porosity by diffusion mechanism. Originality/value This paper has used pure water jetting for BJT of Portland cement-containing bodies.

Graphene/PVDF Composites for Ni-rich Oxide Cathodes toward High-Energy Density Li-ion Batteries

Li-ion batteries (LIBs) employ porous, composite-type electrodes, where few weight percentages of carbonaceous conducting agents and polymeric binders are required to bestow electrodes with electrical conductivity and mechanical robustness. However, the use of such inactive materials has limited enhancements of battery performance in terms of energy density and safety. In this study, we introduced graphene/polyvinylidene fluoride (Gr/PVdF) composites in Ni-rich oxide cathodes for LIBs, replacing conventional conducting agents, carbon black (CB) nanoparticles. By using Gr/PVdF suspensions, we fabricated highly dense LiNi0.85Co0.15Al0.05O2 (NCA) cathodes having a uniform distribution of conductive Gr sheets without CB nanoparticles, which was confirmed by scanning spreading resistance microscopy mode using atomic force microscopy. At a high content of 99 wt.% NCA, good cycling stability was shown with significantly improved areal capacity (Qareal) and volumetric capacity (Qvol), relative to the CB/PVdF-containing NCA electrode with a commercial-level of electrode parameters. The NCA electrodes using 1 wt.% Gr/PVdF (0.9:0.1) delivered a high Qareal of ~3.7 mAh cm−2 (~19% increment) and a high Qvol of ~774 mAh cm−3 (~18% increment) at a current rate of 0.2 C, as compared to the conventional NCA electrode. Our results suggest a viable strategy for superseding conventional conducting agents (CB) and improving the electrochemical performance of Ni-rich cathodes for advanced LIBs.