Studies of Polylactic Acid and Metal Oxide Nanoparticles-Based Composites for Multifunctional Textile Prints

Design and fabrication of La-based perovskites incorporated with functionalized carbon nanofibers for the electrochemical detection of roxarsone in water and food samples

The pentavalent arsenic compound roxarsone (RSN) is used as a feed additive in poultry for rapid growth, eventually ending up in poultry litter. Poultry litter contains chicken manure, which plays a vital role as an affordable fertilizer by providing rich nutrients to agricultural land. Consequently, the extensive use of poultry droppings serves as a conduit for the spread of toxic forms of arsenic in the soil and surface water. RSN can be easily oxidized to release highly carcinogenic As(III) and As(IV) species. Thus, investigations were conducted for the sensitive detection of RSN electrochemically by developing a sensor material based on lanthanum manganese oxide (LMO) and functionalized carbon nanofibers (f-CNFs). The successfully synthesised LMO/f-CNF composite was confirmed by chemical, compositional, and morphological studies. The electrochemical activity of the prepared composite material was examined using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The obtained results confirmed that LMO/f-CNF showed enhanced electrocatalytic activity and improved current response with a good linear range (0.01-0.78 μM and 2.08-497 μM, respectively), exhibiting a low limit of detection (LOD) of 0.004 μM with a high sensitivity of 13.24 μA μM-1 cm-2 towards the detection of RSN. The noteworthy features of LMO/f-CNF composite with its superior electrochemical performance enabled reliable reproducibility, exceptional stability and reliable practical application in the analysis of tap water and food sample, affording a recovery range of 86.1-98.87%.

Solution blowing spinning of polylactate/polyvinyl alcohol/ZnO nanocomposite toward green and sustainable preparation of wound dressing nanofibrous films

The outstanding biodegradability, biocompatibility, affordability, and renewability of polylactic acid have made it a prominent biomaterial. Herein, an innovative, easy, and eco-friendly technique is used to prepare sodium polylactate (SP)-based nanofibers. Solution blowing spinning (SBS) was used to create fibrous mats of SP and polyvinyl alcohol (PVA). SBS's SP nanfibers were crosslinked using an aqueous solution of calcium chloride to produce moisture-resistant calcium polylactate nanofibrous spun mats. Both of UV-visible absorption spectra and transmission electron microscopy were utilized to study the produced zinc oxide (ZnO) nanoparticles (NPs) to indicate a diameter of around 15-23 nm with a high intensity absorption intensity at 370 nm. New polylactate copolymer was synthesized and characterized by infrared and NMR spectroscopic techniques. In order to prepare SP/PVA/ZnO nanocomposite nanofibers, various ZnO ratios were used. The morphologies of the composite nanofibers were investigated by infrared spectroscopy (FTIR), energy-dispersive X-ray analyzer, and scanning electron microscopy. The cytotoxicity tests of the prepared mat were studied by conducting experiments with L-929 cells at various time intervals. The prepared composite SP/PVA/ZnO nanofibers were subjected to cytotoxicity tests to determine their cytocompatibility. Results showed that those with ZnO concentrations between 0.5% and 2% were found to be less harmful than those with higher concentrations. A variety of bacterial species, including Bacillus pumilus and Staphylococcus aureus, as well as Klebseilla pneumoniae and Escherichia coli, were used to test the antibacterial properties of SP/PVA/ZnO spun mats. The ZnO NPs integrated in the SP/PVA fibrous mats were responsible for their antibacterial properties. After finding the appropriate concentration of ZnO that is least harmful while yet giving a satisfactory antibacterial activity, this biomaterial might be perfect for wound dressing applications. HIGHLIGHTS: New eco-friendly biodegradable sodium polylactate (SP) copolymer was synthesized. Zinc oxide nanoparticles (ZnO NPs) with a diameter of 15-23 nm were prepared. High antibacterial SP/PVA/ZnO fibers were prepared by solution blowing spinning. SP/PVA/ZnO nanofibers (180-220 nm) with various ratios of ZnO were presented. Cytotoxicity results showed that the cell viability decreases with increasing ZnO.

Reinforced Structure Effect on Thermo-Oxidative Stability of Polymer-Matrix Composites: 2-D Plain Woven Composites and 2.5-D Angle-Interlock Woven Composites

The thermo-oxidative stability of carbon fiber polymer matrix composites with different integral reinforced structures was investigated experimentally and numerically. Specimens of 2-D plain woven composites and 2.5-D angle-interlock woven composites were isothermally aged at 180 °C in hot air for various durations up to 32 days. The thermal oxidative ageing led to the degradation of the matrix and the fiber/matrix interface. The degradation mechanisms of the matrix were examined by ATR-FTIR and thermal analysis. The interface cracks caused by thermal oxidative ageing were sensitive to the reinforced structure. The thermo-oxidative stability of the two composites was numerically compared in terms of matrix shrinking and crack evolution and then experimentally validated by interlaminar shear tests.

Color-switchable and photoluminescent poly (vinyl chloride) for multifunctional smart applications

Recycled poly (vinyl chloride) (PVC) waste was used to prepare transparent material with long-lasting phosphorescence, photochromic activity, hydrophobicity, strong optical transmission, ultraviolet (UV) protection, and stiffness. Lanthanide-activated aluminate (LaA) microparticles were prepared via the high temperature solid state procedure, which were subjected to the top-down grinding technology to afford LaA nanoparticles (LaAN). Laminated poly (vinyl chloride) bottles were shredded into a transparent plastic matrix, which was combined with LaAN and drop-casted to produce smart materials for a variety of applications. Smart window and photochromic film for smart packaging can be made from recycled poly (vinyl chloride) waste by immobilizing it with various ratios of LaAN. Long-lasting phosphorescent translucent poly (vinyl chloride) smart window and films need LaAN to be evenly dispersed in PVC without clumping. Different analytical methods were employed to assess the materials' morphological structure and chemical composition. Photoluminescence and decay spectra were all employed to investigate the luminescence characteristics. In addition, the mechanical performance was studied. According to CIE Lab (Commission Internationale de L'éclairage) color measurements, this transparent PVC smart material becomes a bright green under UV rays and turns a greenish-yellow in the dark. The PVC luminescence was observed to exhibit an apparent emission bands at 429 and 513 nm when excited at 367 nm. Improvements have been monitored in the UV shielding and hydrophobicity with increasing the phosphor concentration. LaAN-immobilized PVC exhibited reversible photochromism. The present approach can be applied for a variety of applications, such as anticounterfeiting films for smart packaging, smart window, and warning lightening marks.

Multifunctional Dyeing of Wool Fabrics Using Selenium Nanoparticles

This work aims to utilize selenium nanoparticles (Se-NPs) as a novel dyestuff, which endows wool fibers with an orange color because of their localized surface plasmon resonance. The color characteristics of dyed fibers were evaluated and analyzed. The color depth of the dyed fabrics under study was increased with the increase in Se content and dyeing temperature. The colored wool fabrics were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and an X-ray diffraction (XRD) analysis. The results indicated that spherical Se-NPs with a spherical shape were consistently deposited onto the surface of wool fibers with good distribution. In addition, the influence of high temperature on the color characteristics and imparted functionalities of the dyed fabrics were also investigated. The obtained results showed that the proposed dyeing process is highly durable to washing after 10 cycles of washes, and the acquired functionalities, mainly antimicrobial activity and UV-blocking properties, were only marginally affected, maintaining an excellent fastness property.

Sandwich Structures Reflecting Thermal Radiation Produced by the Human Body

Far infrared (FIR) textiles are a new category of functional textiles that have presumptive health and well-being functionality and are closely related to human thermo-physiological comfort. FIR exerts strong rotational and vibrational effects at the molecular level, with the potential to be biologically beneficial. In general, after absorbing either sunlight or heat from the human body, FIR textiles are designed to transform the energy into FIR radiation with a wavelength of 4–14 μm and pass it back to the human body. FIR textiles can meet increased demand for light, warm, comfortable, and healthy clothing. The main aim of this research is to describe the procedure for creating the FIR reflective textile layer as part of multilayer textile structures that have enhanced thermal protection. To develop the active FIR reflecting surface, the deposition of copper nanolayer on lightweight polyester nonwoven structure Milife, which has beneficial properties of low fiber diameters, good shape stability and comfort, was used. This FIR reflective layer was used as an active component of sandwiches composed of the outer layer, insulation layer, active layer, and inner layer. The suitable types of individual layers were based on their morphology, air permeability, spectral characteristics in the infra-red region, and thermal properties. Reflectivity, transmittance, and emissivity were evaluated from IR measurements. Human skin thermal behavior and the prediction of radiation from the human body dependent on ambient conditions and metabolic rate are also mentioned. The FIR reflective textile layer created, as part of multilayer textile structures, was observed to have enhanced thermal protection.

Protective Multifunctional Fibrous Systems Based on Natural Fibers and Metal Oxide Nanoparticles

In recent years, an unprecedented increase in the development of products and technologies to protect the human being has been observed. Now, more than ever, the world population is exposed to several threats, harmful to their well-being and health. Chemical and biological hazardous agents stand out as one of the biggest threats, not only for the military forces, but also for the civilians. Consequently, it's essential to develop personal protective systems that are able to protect their user, not only passively, but actively, being able to detect, adsorb, degrade and decontaminate pesticides, pollutants, microorganisms and most importantly: chemical/biological warfare agents. One recent strategy for the development of active fibrous structures with improved functions and new properties is their functionalization with nanoparticles (NPs), especially metal oxides. Although their known effectiveness in the decomposition of harmful agents, the NPs could also include other functionalities in the same structure using low quantities of material, without adding extra weight, which is of huge importance for a soldier in the battlefield. The use of natural fibers as the substrate is also very interesting, since this material is a much sustainable alternative when compared to synthetic ones, also providing excellent properties.

Biogenic Nanoparticles: Synthesis, Characterisation and Applications

Nanotechnology plays a big part in our modern daily lives, ranging from the biomedical sector to the energy sector. There are different physicochemical and biological methods to synthesise nanoparticles towards multiple applications. Biogenic production of nanoparticles through the utilisation of microorganisms provides great advantages over other techniques and is increasingly being explored. This review examines the process of the biogenic synthesis of nanoparticles mediated by microorganisms such as bacteria, fungi and algae, and their applications. Microorganisms offer a disparate environment for nanoparticle synthesis. Optimum production and minimum time to obtain the desired size and shape, to improve the stability of nanoparticles and to optimise specific microorganisms for specific applications are the challenges to address, however. Numerous applications of biogenic nanoparticles in medicine, environment, drug delivery and biochemical sensors are discussed.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

This assessment by the Environmental Effects Assessment Panel (EEAP) of the United Nations Environment Programme (UNEP) provides the latest scientific update since our most recent comprehensive assessment (Photochemical and Photobiological Sciences, 2019, 18, 595-828). The interactive effects between the stratospheric ozone layer, solar ultraviolet (UV) radiation, and climate change are presented within the framework of the Montreal Protocol and the United Nations Sustainable Development Goals. We address how these global environmental changes affect the atmosphere and air quality; human health; terrestrial and aquatic ecosystems; biogeochemical cycles; and materials used in outdoor construction, solar energy technologies, and fabrics. In many cases, there is a growing influence from changes in seasonality and extreme events due to climate change. Additionally, we assess the transmission and environmental effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is responsible for the COVID-19 pandemic, in the context of linkages with solar UV radiation and the Montreal Protocol.

Sustainable Use of Nanomaterials in Textiles and Their Environmental Impact

At present, nanotechnology is a priority in research in several nations due to its massive capability and financial impact. However, due to the uncertainties and abnormalities in shape, size, and chemical compositions, the existence of certain nanomaterials may lead to dangerous effects on the human health and environment. The present review includes the different advanced applications of nanomaterials in textiles industries, as well as their associated environmental and health risks. The four main textile industry fields using nanomaterials, nanofinishing, nanocoatings, nanofibers, and nanocomposites, are analyzed. Different functional textiles with nanomaterials are also briefly reviewed. Most textile materials are in direct and prolonged contact with our skin. Hence, the influence of carcinogenic and toxic substances that are available in textiles must be comprehensively examined. Proper recognition of the conceivable benefits and accidental hazards of nanomaterials to our surroundings is significant for pursuing its development in the forthcoming years. The conclusions of the current paper are anticipated to increase awareness on the possible influence of nanomaterial-containing textile wastes and the significance of better regulations in regards to the ultimate disposal of these wastes.

Preparation and Characterization of Self-Dispersing Phthalocyanine Blue 15:4 Pigment for Dyeing of Wool Textiles

A self-dispersing pigment was produced by a diazonium coupling reaction; the pigment reacted with aromatic diazonium salts which were generated by the reaction of p-aminobenzene sulfonic acid and sodium nitrite. The surface of the pigment particles was negatively charged due to sulfonic acid groups on the pigment surface. The pigment particle size and zeta potential were, respectively, 134.5 nm and −45.4 mV at neutral pH. The wool surface was positively charged by adjusting the pH; then the anionic self-dispersing pigment dyed the cationic wool. The results show that self-dispersing pigment can adhere well without a binder, and that the K/S value is closely related to pH, dyeing time, and the amount of pigment. The color fastness of the wool was good and the light fastness of the wool was grade 5, which is better than acid dyes. Self-dispersing pigments are potential candidates for dyeing high-weather-resistance textiles.

Khattab T. Recent Advances in Cellulose-Based Biosensors for Medical Diagnosis

Cellulose has attracted much interest, particularly in medical applications such as advanced biosensing devices. Cellulose could provide biosensors with enhanced biocompatibility, biodegradability and non-toxicity, which could be useful for biosensors. Thus, they play a significant role in environmental monitoring, medical diagnostic tools, forensic science, and foodstuff processing safety applications. This review summarizes the recent developments in cellulose-based biosensors targeting the molecular design principles toward medical detection purposes. The recognition/detection mechanisms of cellulose-based biosensors demonstrate two major classes of measurable signal generation, including optical and electrochemical cellulosic biosensors. As a result of their simplicity, high sensitivity, and low cost, cellulose-based optical biosensors are particularly of great interest for including label-free and label-driven (fluorescent and colorimetric) biosensors. There have been numerous types of cellulose substrates employed in biosensors, including several cellulose derivatives, nano-cellulose, bacterial cellulose, paper, gauzes, and hydrogels. These kinds of cellulose-based biosensors were discussed according to their preparation procedures and detection principle. Cellulose and its derivatives with their distinctive chemical structure have demonstrated to be versatile materials, affording a high-quality platform for accomplishing the immobilization process of biologically active molecules into biosensors. Cellulose-based biosensors exhibit a variety of desirable characteristics, such as sensitivity, accuracy, convenience, quick response, and low-cost. For instance, cellulose paper-based biosensors are characterized as being low-cost and easy to operate, while nano-cellulose biosensors are characterized as having a good dispersion, high absorbance capacity, and large surface area. Cellulose and its derivatives have been promising materials in biosensors which could be employed to monitor various bio-molecules, such as urea, glucose, cell, amino acid, protein, lactate, hydroquinone, gene, and cholesterol. The future interest will focus on the design and construction of multifunctional, miniaturized, low-cost, environmentally friendly, and integrated biosensors. Thus, the production of cellulose-based biosensors is very important.

Facile Fabrication of Methylcellulose/PLA Membrane with Improved Properties

With the rapid exhaustion of fossil resources, and environmental pollution relative to the use of fossil-based products, developing eco-friendly products using biomass and/or biodegradable resources is becoming increasingly conspicuous. In this study, ecofriendly and biodegradable composite membranes containing varying MC/PLA (methylcellulose/polylactic acid) mass ratios were prepared. The properties and structures of the MC/PLA membranes were studied by mechanical testing, 13C NMR techniques, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and hot compression. The MC/PLA membranes displayed markedly improved tensile strength and elongation at the MC/PLA mass ratio range of 99:1 to 9:1. The tensile strength and elongation of the MC/PLA (97:3) membrane was found to be the optimum, at 30% and 35% higher than the neat MC, respectively. It was also found that hot compression could improve the tensile strength and elongation of the membranes. At the same time, the membranes showed enough good thermal stability. In addition, the effect of MC/PLA mass ratio on morphologies of the membranes were studied by microscopy technique.

Multifunctional Stretchable Conductive Woven Fabric Containing Metal Wire with Durable Structural Stability and Electromagnetic Shielding in the X-Band

Elastomeric, conductive composite yarns have recently received attention around the opportunity for them to offer special protective fields. A straightforward approach for fabricating tri-component elastic-conductive composite yarns (t-ECCYs) containing stainless steel wire (SSW) was proposed previously. This work mainly focuses on the electromagnetic shielding effectiveness (EMSE) of weft-stretchable woven fabric containing t-ECCY over the X-band under different testing conditions, e.g., single step-by-step elongation, cyclic stretch and lamination events. Results showed that a woven cotton fabric with weft yarn of t-ECCY not only exhibited superior weft stretch-ability to a higher elongation (>40%) compared with a pure cotton control but also had an acceptable 15-cyclic stability with 80% shape recovery retention. The t-ECCY weft fabric was effective in shielding electromagnetic radiation, and its EMSE was also enhanced at elevated elongations during stretch at parallel polarization of EM waves. There was also no decay in EMSE before and after the t-ECCY fabric was subject to 15 stretch cycles at extension of 20%. In addition, a 90° by 90° cross lamination of t-ECCY fabric remarkably improved the EMSE compared to a 0°/90° one. The scalable fabrication strategy and excellent EMSE seen in t-ECCY-incorporated fabrics represent a significant step forward in protective fields.