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The purpose of this paper is to investigate the potential for using chitin and chitosan sustainable materials to absorb copper from PCB manufacturing effluent and to report the results of an initial feasibility study aimed at demonstrating proof of concept.

Crab shells and prawn shells, both waste products of the seafood industry, as well as chitosan, were evaluated as potential absorbents for recovering copper present at low levels in the manufacturing effluent produced in a UK‐based PCB manufacturing facility. Various conditions were investigated and efforts were also made to recover absorbed copper via a regeneration process that enabled the metal to be electroplated from solution.

Although only a short feasibility study, conditions were found that enabled copper to be absorbed by the ground crab shells and chitosan and then subsequently recovered by electrowinning to produce the metal.

Although successful as a feasibility study, the experimental work highlighted the large number of variables that need to be investigated and optimised in order to obtain the most efficient copper capture and recovery. Further work needs to be carried out to determine these optimum conditions and to investigate the potential for recovery of other metals from a wider range of solutions.

The paper details how individual treatment technologies can be combined to enable a much more sustainable approach to PCB manufacturing which offers the benefits of reduced effluent metal levels, metal recovery and a novel use for another sector's waste products.

The purpose of this paper is to analyze the effects of chitosan treatments on exerted pressures of nylon 6.6/elastane pressure garments in three different knit structures using wireless pressure sensors for an accurate and a precise scar management for future designs.

Pressure garments designed in different structures consist of 70/30 and 75/25 nylon 6.6/elastane were treated with chitosan and the exerted pressures were analyzed using wireless pressure sensors including ultra-thin and flexible printed circuit sensors in comparison with untreated control samples. Antimicrobial activities and washing tests were also evaluated.

It is found that chitosan treatments have a significant effect on final pressures. Exerted pressures increased significantly for all samples after chitosan treatments. Higher pressures were measured for weft knit structured designs while lower pressures were recorded for powernet structured garments. It is found that the elasticity showed a small significant decrease and it has attributed due to a small significant shrinkage during processes. The mean scores of pressures were found in the acceptable medical range which will continue to help hypertrophic scar management for future designs. The exerted pressures of the fabrics remained constant after five washes and showed a small significant decrease after 10 and 50 washes which will provide a long period of compression. Permanent antimicrobial effectiveness has gained at around 90 percent after five washes and 50 percent after 50 washes. A small significant increase was observed for stiffness (CD, MD) after ten washes.

Chitosan treatments impact exerted pressures of pressure garments significantly. It is a reference to evaluate pressure functions of pressure garments using wireless pressure sensors while imparting antimicrobial activity.

This study aims to use multi-functional viscose fabric that was facilely developed with with respect to ease and care characteristics, reinforcement effect and antibacterial activity by using novel echo friendly antibacterial finish based on citric acid/sodium hypophosphite and the authors’ previously tailor-made poly meth acrylic acid (MAA)-chitosan graft copolymer via alternative microwave curing approach instead of traditional high-temperature cure one.

Viscose fabric was paddled twice in the cross-linking formulations containing different concentrations of citric acid, poly (MAA)-chitosan graft copolymer and sodium hypophosphite to 90 % wet pick up and dried at 100°C for 3 min in an electric oven. Then, the treated fabrics were placed on the disk spinner of the microwave oven and cured at different power (100–800 Watt) for various durations (60–180 s). The fabric was then water-rinsed and dried at ambient condition before use.

Results revealed that the above echo friendly method for finished viscose fabrics was found to achieve relatively high dry wrinkle recovery angle and maintain the loss in tensile strength within the acceptable range, as well as antibacterial activity against Escherichia coli and Staphylococcus aureus as a gram-negative and gram-positive bacteria, respectively; in addition to durability up to ten washing cycles. Furthermore, scanning electron microscope images, nitrogen content and add on % of the finished fabric confirmed the penetration of grafted chitosan inside the fabric structure. The tentative mechanism for these reactions is advocated.

The novelty addressed here is undertaken with the advantages of using citric acid as a nonformaldehyde, safe and cheap poly carboxylic acid as a crosslinking agent and sodium hypophosphite as a potential catalyst, in addition to the authors’ noncitable multifunctional echo friendly tailor-made poly (MAA)-chitosan graft copolymer for imparting reinforcement and antibacterial characteristics to viscose fabric that uses the pad-dry/cure microwave fixation for progressively persuaded heat within the fabric during curing.

This was done to see the impact of microwave as green and efficient tool with respect to reduction in organic solvents, chemicals and exposer time as well as fixation temperature on the finishing reaction in comparison with traditional pad-dry-cure method.

Poly (MAA)-chitosan graft copolymer as amphoteric biopolymer was expected to impart multifunctional properties to viscose fabrics especially with comparable dry wrinkle recovery angle and minimize the loss in tensile strength in addition to antibacterial properties in comparison with untreated one.

The fabrication and characterization of a hydrogel-based conductometric sensor have been carried out. The purpose of this research is to fabricate a small robust hydrogel-based conductometric sensor for real-time monitoring of pH in the physiological range.

A pH-responsive Chitosan/Gelatin composite hydrogel has been used for this purpose. This study reports and analyzes the sensing response obtained from four hydrogel compositions with varying Chitosan/Gelatin ratios. The pH-responsive nature of the hydrogel has been mapped out through volumetric and conductometric tests. An attempt has been made to correlate these characteristics with the physico-chemical nature of the hydrogel through scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques.

The four hydrogel compositions differed on the basis of gel composition ratios; the conductometric analysis results prove that the sensor with the hydrogel composition (Chitosan 2 per cent, Gelatin 7 per cent, ratio 1:2) produces the best pH resolution in the pH range of 4 to 9. The sensing mechanisms and the differences obtained between individual sensor outputs have been discussed in detail. On the basis of this extensive in vitro assessment, it has been concluded that while key pendant functional groups contribute to pH-responsive characteristics of the hydrogel, the overall sensitivity of the sensors gel component to surrounding pH is also determined by the crystalline to amorphous ratio of the hydrogel composite, its interpenetrating cross-linked structure and the relative ratio of the hydrophilic to the pH-sensitive components.

The conductometric sensor results prove that the fabricated sensor with the shortlisted hydrogel composition shows good sensitivity in the physiological pH range (4 to 9) and it has the potential for use in point of care medical devices for diagnostic purposes.

This is the first reported version of the fabrication and testing and analysis/comparison of a hydrogel-based conductometric sensor based on this composition. The work is original and has not been replicated anywhere.

Enzymatic desizing using α-amylase is the conventional and eco-friendly method of removing starch based size. Conventionally, enzymes are drained after completion of process; being catalysts, they retain their activity after reaction and need to be reused. Immobilization allows the recovery of enzymes to use them as realistic biocatalyst. This study aims to recover and reuse of α-amylase for desizing of cotton via immobilization.

This paper investigates the application of α-amylase immobilized on Chitosan and Eudragit S-100 for cotton fabric desizing. A commercial α-amylase was immobilized on reversibly soluble-insoluble polymers to work out with inherent problems of heterogeneous reaction media. The immobilization process was optimized for maximum conjugate activity, and immobilized amylases were applied for grey cotton fabric desizing.

The desizing performance of immobilized amylases was evaluated in terms of starch removal and was compared to free enzyme. The immobilized amylases showed adequate desizing efficiency up to four cycles of use and were recovered easily at the end of each cycle. The amylase immobilized on Eudragit is more efficient for a particular concentration than chitosan.

Immobilization associates with insolubility and increased size of enzymes which lead to poor interactions and limited diffusion especially in textiles where enzymes have to act on macromolecular substrates (heterogeneous media). The selection of support materials plays a significant role in this constraint.

The commercial α-amylase was covalently immobilized on smart polymers for cotton fabric desizing. The target was to achieve immobilized amylase with maximum conjugate activity and limited constraints. The reversibly soluble-insoluble polymers support provide easy recovery with efficient desizing results in heterogeneous reaction media.

Any change in physical performance of the fibre corresponds to a change in its molecular structure. Basically polyester is hydrophobic in nature due to the absence of attracting polar groups and the dense packing in its polymeric structure. Due to the dense packing in polymeric structure and lack of hydroxyl groups of polyester it does not absorb water hence breathability is poor. The possibility of using air and oxygen plasma treatments for fibre surface activation to facilitate the improvement of hydrophilicity is attempted and has been improved. The purpose of this paper is to study the possibility of engineering the multifunctional of fabrics.

The treated fabric is evaluated through measuring the ultraviolet protection factor, thermal resistance, and antibacterial activity properties. Scanning electron microscopy and transmission electron microscopy graphs show deposition of nano particles (NPs) of Chitosan, TiO₂ and ZnO onto the fibre after washing several times.

Air plasma-nano Chitosan treatment affects positively the antibacterial activity, thermal resistance of the fibre and air plasma-nano TiO₂ and ZnO the fibre protection against ultraviolet rays. Furthermore, the plasma treatment solves an environmental problem which offers safe production process and working place and decreases the unit cost.

The authors are confident that textiles will adopt this technology in the future.

This study aims to propose that the corrosion resistance of the neat epoxy coating can be further enhanced by incorporating reinforcing agents.

Chitosan, silica and their hybrid compound were used to study the subject of corrosion resistance of epoxy coating systems. This work used 3.5 Wt.% NaCl solution as the electrolyte, and electrochemical impedance spectroscopy (EIS) was used to investigate the electrochemical behaviour of the studied coating systems. Standard and accelerated states were used without and with scratch on the coating layer.

It was found that the impedance value of composite coating incorporated with the hybrid compound was significantly higher at 10¹⁰ Ω after 14 days of exposure in both testing states. The breakpoint frequency (f_b) determination also proves with large capacitive region at low-to-high frequency of impedance plots corresponding to the high corrosion resistance.

The hybrid compound consisting of chitosan as organic biopolymer and silica as inorganic material, respectively, served as a promising reinforcing agent for composite coating as a promising corrosion inhibitor. Different states of EIS measurement were used which are standard (without scratch) and accelerated (with scratch) states associated with the f_b values.

Methylene blue (MB) is classified as a cationic dye which is widely used as chemical indicator, coloring agent and biological stain. The discharge of this dye to the water streams is harmful to the human beings. For this reason, this study investigated the removal of MB from aqueous solution by hydrogel nanocomposite.

In experimental part, at first, ultraviolet (UV)-curable hydrogel/chitosan nanocomposite, which improves its elasticity by urethane acrylate, was synthesized and characterized by FTIR and SEM analysis. Afterward, the synthesized hydrogel nanocomposite was applied for the removal of MB and the influence of operational condition including nanocomposite loading, dye concentration, contact time and pH of solution was specified. Moreover, isotherm studies as well as kinetics survey were performed.

Langmuir, Freundlich, Brunauer, Emmett and Teller and Tempkin adsorption isotherms were assessed for the analysis of experimental data indicating the Freundlich isotherm was the best fitted one. The adsorption kinetics data was examined indicating the adsorption kinetics appropriate to pseudo-second-order kinetics model.

The predominant water absorption property of the UV-curable hydrogel/chitosan nanocomposite to 8.5 steps and outstanding adsorption capacity for the elimination of MB on hydrogel nanocomposite subscribed that the synthesized hydrogel could be a favorable adsorbent for simultaneous absorption of water and removal of cationic dyes.

This study aimed to present fabrication of novel poly(lactic acid) (PLA) mediated chitosan nanoparticles (CNPs) and their impregnation on cotton fabric for enhanced antibacterial and physical properties.

The PLA-CNPs were characterized using scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta size analysis. The prepared PLA-CNPs were impregnated on cotton fabric via pad-dry-cure method. The finished cotton fabric was then characterized for its antibacterial activity, functional and other physical textile properties.

The spectral and optical properties demonstrate that the NPs expressed spherical morphologies with an average particle diameter of 88.02 nm. The antibacterial activity of treated fabrics ranged between 75 and 90 per cent depending on the concentration of PLA-CNPs.

Because of enhanced awareness and desire for ecofriendly products, the use of sustainable and functional textiles is increasing day by day. For the said purpose, industries are using different chemical treatments to achieve desired end functionality. Currently, different synthetic antibacterial agents are in practice, but they lack sustainable approach to save the environment. In this study, the researchers have developed PLA mediated CNPs for sustainable antibacterial and physical properties of treated cotton fabric.

To the best of the authors’ knowledge, this is first attempt to fabricate PLA-incorporated CNPs for application on cotton fabric followed by a detailed characterization.

The aim of this research is to investigate the influence of low molecular weight chitosan (LWCS) on the dyeability of cotton fabrics. Various concentrations of hydrogen peroxide were used to degrade chitosan to LWCS, which was used to pretreat cotton fabrics under different conditions in order to determine its influence on subsequent acid dyeing of the fabrics. The results showed that the molecular weight of LWCS decreased with increasing concentration of hydrogen peroxide. Additionally, LWCS pretreatment of cotton fabric is beneficial for acid dyeing. The K/S values for fabric dyeing increased with a decrease in LWCS molecular weight and the concomitant increase in concentration; a concentration of 4% LWCS yielded the best result. The anti-bacterial properties of fabrics pretreated with LWCS were better than those pretreated with chitosan. The dye and anti-bacterial fastness after 20 washes were best for fabrics pretreated with LWCS.