Antimicrobial Coatings for Medical Textiles via Reactive Organo-Selenium Compounds.

Bleached and cationized cotton fabrics were chemically modified with reactive organoselenium compounds through the nucleophilic aromatic substitution (SNAr) reaction, which allowed for organo-selenium attachment onto the surface of cotton fabrics via covalent bonds and, in the case of the cationized cotton fabric, additional ionic interactions. The resulting textiles exhibited potent bactericidal activity against S. aureus (99.99% reduction), although only moderate activity was observed against E. coli. Fabrics treated with reactive organo-selenium compounds also exhibited fungicidal activities against C. albicans, and much higher antifungal activity was observed when organo-selenium compounds were applied to the cationized cotton in comparison to the bleached cotton. The treatment was found to be durable against rigorous washing conditions (non-ionic detergent/100 °C). This paper is the first report on a novel approach integrating the reaction of cotton fabrics with an organo-selenium antimicrobial agent. This approach is attractive because it provides a method for imparting antimicrobial properties to cotton fabrics which does not disrupt the traditional production processes of a textile mill.

Cryogenic grinding of cotton fiber cellulose: The effect on physicochemical properties.

The study evaluated the effect of cryogrinding, a relatively new, cost-effective, and sustainable mechanical treatment method, on physicochemical properties of two different micronaire (3.6- and 5.3-) cotton fiber cellulose. Native (type I), mercerized (type II), and acidulated cellulose were subjected to cryogrinding for 48 and 96 min, and their physicochemical properties were investigated. The results demonstrated that cryogrinding resulted in partial amorphization of native and mercerized celluloses, particle size decrease, and a slight reduction of T50%. Importantly, degree of polymerization (DP) of native cellulose reduced significantly: more than two-fold after 12 cycles and more than three-fold after 24 cycles of cryogrinding. No difference in properties was found between 3.6- and 5.3-micronaire cellulose. Advantageous impacts of cryogrinding found in this work will help signify the potential of this technique in cellulose processing and enable the identification of areas for future development.

Utilization of Cellulose to Its Full Potential: A Review on Cellulose Dissolution, Regeneration, and Applications.

As the most abundant natural polymer, cellulose is a prime candidate for the preparation of both sustainable and economically viable polymeric products hitherto predominantly produced from oil-based synthetic polymers. However, the utilization of cellulose to its full potential is constrained by its recalcitrance to chemical processing. Both fundamental and applied aspects of cellulose dissolution remain active areas of research and include mechanistic studies on solvent-cellulose interactions, the development of novel solvents and/or solvent systems, the optimization of dissolution conditions, and the preparation of various cellulose-based materials. In this review, we build on existing knowledge on cellulose dissolution, including the structural characteristics of the polymer that are important for dissolution (molecular weight, crystallinity, and effect of hydrophobic interactions), and evaluate widely used non-derivatizing solvents (sodium hydroxide (NaOH)-based systems, N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl), N-methylmorpholine-N-oxide (NMMO), and ionic liquids). We also cover the subsequent regeneration of cellulose solutions from these solvents into various architectures (fibers, films, membranes, beads, aerogels, and hydrogels) and review uses of these materials in specific applications, such as biomedical, sorption, and energy uses.

Production and Surface Modification of Cellulose Bioproducts.

Petroleum-based synthetic plastics play an important role in our life. As the detrimental health and environmental effects of synthetic plastics continue to increase, the renewable, degradable and recyclable properties of cellulose make subsequent products the "preferred environmentally friendly" alternatives, with a small carbon footprint. Despite the fact that the bioplastic industry is growing rapidly with many innovative discoveries, cellulose-based bioproducts in their natural state face challenges in replacing synthetic plastics. These challenges include scalability issues, high cost of production, and most importantly, limited functionality of cellulosic materials. However, in order for cellulosic materials to be able to compete with synthetic plastics, they must possess properties adequate for the end use and meet performance expectations. In this regard, surface modification of pre-made cellulosic materials preserves the chemical profile of cellulose, its mechanical properties, and biodegradability, while diversifying its possible applications. The review covers numerous techniques for surface functionalization of materials prepared from cellulose such as plasma treatment, surface grafting (including RDRP methods), and chemical vapor and atomic layer deposition techniques. The review also highlights purposeful development of new cellulosic architectures and their utilization, with a specific focus on cellulosic hydrogels, aerogels, beads, membranes, and nanomaterials. The judicious choice of material architecture combined with a specific surface functionalization method will allow us to take full advantage of the polymer's biocompatibility and biodegradability and improve existing and target novel applications of cellulose, such as proteins and antibodies immobilization, enantiomers separation, and composites preparation.

Recent Advances in Biopolymer-Based Dye Removal Technologies.

Synthetic dyes have become an integral part of many industries such as textiles, tannin and even food and pharmaceuticals. Industrial dye effluents from various dye utilizing industries are considered harmful to the environment and human health due to their intense color, toxicity and carcinogenic nature. To mitigate environmental and public health related issues, different techniques of dye remediation have been widely investigated. However, efficient and cost-effective methods of dye removal have not been fully established yet. This paper highlights and presents a review of recent literature on the utilization of the most widely available biopolymers, specifically, cellulose, chitin and chitosan-based products for dye removal. The focus has been limited to the three most widely explored technologies: adsorption, advanced oxidation processes and membrane filtration. Due to their high efficiency in dye removal coupled with environmental benignity, scalability, low cost and non-toxicity, biopolymer-based dye removal technologies have the potential to become sustainable alternatives for the remediation of industrial dye effluents as well as contaminated water bodies.

Cellulose porosity improves its dissolution by facilitating solvent diffusion.

This paper reports on the effect of improved porous characteristics of cellulose on its solubility in DMAc/LiCl. The use of freeze-drying (FD) treatment led to higher surface area and void fraction of volume for high-molecular-weight (HMW) cotton cellulose (DP~5000). Improvement in porous characteristics of cellulose did not change the chemical and crystalline structures of cellulose, as compared to hot-drying (HD) treatment. However, significant improvement in the dissolution of FD-HMW cellulose in DMAc/LiCl was observed under relatively low temperature (80 °C). The relationship between the solubility and the porous characteristics of cellulose was discussed using Stokes-Einstein Equation and effective diffusion coefficient equation. It was concluded that the increase in the diffusion coefficient of the solvent and the improvement in the porous characteristics of cellulose played key roles to enhance the diffusion rate of the solvent through the cellulose molecular network.