SciCombinator

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Journal: Carbohydrate polymers

28

This review article is undertaken with a view to survey important scientific research and developmental works pertaining to antibacterial modification of textiles using nanotechnology as a new means to achieve such textiles. Inevitably, conventional antimicrobial agents and their applications to textiles are reported. This is followed by a focus on inorganic nanostructured materials that acquire good antibacterial activity and application of these materials to the textiles. Evaluation of the antibacterial efficacy is described. An outlook which envisions the importance of using nanotechnology in the antibacterial finishing of textiles is also outlined.

Concepts: Application software, Antimicrobial, Microbiology, Science, Scientific method, Textile, Research, Tea tree oil

28

This review focuses on hyaluronic acid (HA) tissue scaffolding materials. Scaffolds are defined in terms of formation mechanisms and mode of action. Solution properties are discussed as an understanding of the hydrodynamics of HA is fundamental in optimising the subsequent modification and the chemistries behind important tissue engineering applications that are emerging from recent research on this increasingly valuable carbohydrate polymer are described. Key scaffold characteristics such as mechanical, biological function and degradation are discussed. The latest technologies behind scaffold processing are assessed and the applications of HA based scaffolds are discussed.

Concepts: Scaffolding, Engineering

28

Mucoadhesive polymeric nanoparticles intended for drug transport across the gastrointestinal mucosa were prepared from quaternary ammonium-chitosan conjugates synthesised from reduced-MW chitosan (32 kDa). Conjugates contained pendant moieties of 2-4 adjacent diethyl-dimethylene-ammonium groups substituted on repeating units (26-55%). Conjugates were thiolated via amide bonds with thioglycolic acid to yield products with thiol content in the 35-87 ╬╝mol/g range. Nanoparticles with mean size in the 270-370 nm range and positive zeta-potential (+3.7 to +12.5 mV) resulted from ionotropic gelation of the thiolated conjugates with de-polymerised hyaluronic acid (470 kDa). The nanoparticles were fairly stable in size and thiol content and showed a significant mucoadhesivity, matching and even exceeding that of the constituent polymers. Nanoparticles were internalised by endothelial progenitor cells in direct relation to their surface charge intensity. Nanoparticle uptake significantly improved cell viability and resistance to oxidation. The lyophilised nanoparticles were re-dispersible and could make a manageable formulation for oral use.

Concepts: Ammonia, Polymer, Nanoparticle, Carbonyl, Colloid, Sol-gel, Hydrogen, Protein

28

Two types of ionic liquids, 1-ethyl-3-methylimidazolim acetate and 1-ethyl-3-methylimidazolium lactate, were employed for the direct processing of pine wood into microfibers. The concentration of 5 wt.% of wood in ionic liquids was rated as the most appropriate for electrospinning. The fibers were electrospun into the collector water bath. The final structure varied from individual microfibers to fiber bundles. It was demonstrated that 1-ethyl-3-methylimidazolium lactate is a powerful solvent and provides the direct transformation of pristine pine wood into the non-wovens.

Concepts: Deep eutectic solvent, Surface tension, Pinophyta, Ionic liquid, Water, Solvent, Liquid, Solution

28

There exists a misunderstanding on the TAED-activated peroxide system in the textile industry that H(2)O(2) used in excess of the stoichiometric amount could produce an addition effect on bleaching of cotton under alkaline conditions. In this study, a critical reinvestigation was carried out on the TAED-activated peroxide system for bleaching of cotton. It was found that the TAED-activated peroxide system achieved its best performance under near-neutral pH conditions. No addition effect was observed when an excessive amount of H(2)O(2) was used under alkaline conditions, which is probably due to the base-catalyzed bimolecular decomposition of peracetic acid and the nucleophilic attack by H(2)O(2) on peracetic acid. NaHCO(3) was shown to be a desired alkaline agent for maintaining near-neutral pH for the TAED-activated peroxide system. This study provides new insight into the application of the TAED-activated peroxide system for low-temperature bleaching of cotton under more environmentally benign conditions.

Concepts: Cotton, Textile, Tetraacetylethylenediamine, Base, PH, Hydrogen peroxide, Ammonia, Oxygen

28

Polysaccharides (GNF) from Acacia mearnsii de Wild gum exudates, collected from trees growing in the south of Brazil, were characterized ((13)C and HSQC NMR, GC-MS, colorimetric assays). A commercial gum arabic (GAC) was analyzed similarly and compared with GNF. There were differences, consistent with distinct behavior in tensiometry tests and as emulsion stabilizer. GNF had a higher protein content than GAC, with small differences in the monosaccharide composition, the greater one being the lower uronic acid content of GNF (4%), compared with GAC (17%). GNF had a much broader molecular mass distribution, M(w)/M(n), and a lower M(w). GNF was more efficient in lowering the surface tension of water and saline solutions and was more efficient in emulsifying castor oil droplets. Results were discussed taking into account structural and molecular differences between the studied gums. It was concluded that polysaccharides from A. mearnsii de Wild are candidates as substitutes of currently commercialized arabic gums (Acacia senegal and Acacia seyal) having, depending on their application, improved properties.

Concepts: Liquid, Acacia seyal, Acacia senegal, Surface tension, Acacia mearnsii, Water, Gum arabic, Acacia

28

Nanoparticles have been increasingly used to improve the properties of textile fabrics. Viscose and polyester fabrics are treated with SiO(2) nanoparticle by another technique than the conventional sol-gel method in presence of binder (acrylate based copolymer). The effect of the content of SiO(2) nanoparticle on the physical properties of the treated fabrics such as moisture regain, tensile strength and elongation % were investigated. Furthermore, the antibacterial activity and coloration properties of pretreated fabrics were evaluated. Characterizations of pretreated samples by infrared spectroscopy and scanning electron microscopy were also conducted. The results show that the physical and coloration properties of pretreated samples were improved. The treated viscose fabric showed outstanding antibacterial performance against both Escherichia coli (G-) and Staphylococcus aureus (G+). Excellent durability of the treatment to repeated home laundering toward antibacterial and coloration properties was obtained in presence of binder.

Concepts: Gold, Staphylococcus aureus, Escherichia coli, Nanoparticle, Scanning electron microscope, Polyester, Sol-gel, Textile

28

This research mainly deals with a novel flame-retardant and UV-protection for cellulosic fabrics using ZnO nanoparticles. We present the preparation and application of ZnO nanoparticles. The size of the prepared nanoparticles was analysed using dynamic light scattering (DLS). The application of nano ZnO on cellulosic fabrics (cotton 100% and cotton/cotton polyester 65/35%) was achieved by using different polycarboxilic acids (succinic acid [SA] and 1,2,3,4-butane tetracarboxilic acids [BTCA]) with sodium hypophosphite (SHP) as catalyst through conventional pad-dry-cure method. The effect of concentration of SHP on the physical properties, flammability and UV-protection of cross-linked fabrics are investigated. The effect of concentration of zinc oxide nanoparticles and the effect of curing temperature were also investigated. The results revealed the importance of SHP in increasing the flame-redundancy of the treated cellulosic fabrics.

Concepts: Dynamic light scattering, Light scattering, Titanium dioxide, Sunscreen, Textile, Zinc oxide, Zinc, Ultraviolet

28

Rheological properties of welan gum and xanthan gum solutions have been characterized systematically at various concentrations, temperatures and salinities. It is found that the viscoelasticity of welan gum is higher than that of xanthan gum at the same condition though the molecular weight of welan gum is lower. In view of this, welan gum will make a good performance in enhanced oil recovery, especially in high temperature and high salinity reservoirs. Network structure can be formed in solutions of welan gum and xanthan gum for the dynamic modulus has exponential relationship with the concentration. Moreover, the molecular aggregates of welan gum adopt a different arrangement with that of xanthan gum, adjacent double helices of welan gum arrange in parallel as the zipper model. The structure formed by zipper model is still stable in high temperature and high salinity.

Concepts: Gums, Chemical properties, E number, Liquid, Solution, Xanthan gum, Concentration, Chemistry

28

Highly effective cellulose solvents for the dissolution of cellulose at ambient temperature have been designed by adding any aprotic polar solvent to 1-butyl-3-methylimidazolium acetate ([C(4) mim][CH(3)COO]). The effects of molar ratio of the aprotic polar solvents to [C(4) mim][CH(3)COO], anionic structure of the ionic liquids (ILs) and nature of the co-solvents on cellulose solubility have been studied in detail. The enhanced dissolution of cellulose is suggested to be mainly resulted from the preferential solvation of cations of the ILs by the aprotic polar solvents, and this has been supported by our conductivity measurements.

Concepts: Ethanol, Solution, Tetrahydrofuran, Deep eutectic solvent, Ionic liquid, Acetic acid, Solubility, Solvent