Physiochemical and optical properties of chitosan based graphene oxide bionanocomposite

In the present investigation an ecofriendly approach and a simple homogeneous solution casting method led to the development of biodegradable chitosan/graphene oxide bionanocomposites. The formation of bionanocomposite was confirmed by UV–vis, FT-IR, Raman spectroscopy, XRD, and further evaluated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The circular dichroism (CD) study of chitosan/graphene oxide revealed that the intensity of the negative transition band at wavelength of 200–222 nm decreased with the different pH of chitosan/graphene oxide solutions. It was also found that the pH conditions affect the interaction between chitosan and graphene oxide. Optical properties of chitosan/graphene oxide are evaluated by photoluminescence (PL) spectroscopy which showed blue shift at excitation wavelength of 255 nm compared to graphene oxide. These results strongly suggest that the bionanocomposite materials may open new vistas in biotechnological, biosensor and biomedical applications

Dyeing Chemicals

Dyeing auxiliaries play an important role in the determination of the final dyeing quality. The formation of additional complexes with dyes and auxiliary agents enhances the exhaustion of dyes on textile substrates. For aqueous-based dyeing, dye auxiliaries such as chelating agents, dispersing agents, leveling agents, electrolyte, pH control agents, and surfactants form complexes with the dye on natural and synthetic fibers. A growing awareness of the impact of industrial pollution on the environment became crucial for the dyeing industry in the closing decades of the twentieth century. These chapters discuss the characteristics of dyeing chemicals and how auxiliary substances can assist in achieving outstanding dyeing performance

Sustainable Textile Processing by Enzyme Applications

Enzymatic treatments have gained popularity in the textile industry because of environmental friendly and energy conserving alternatives. Advancement in biotechnology and modification of enzymes has been focused based on various textile process applications. All the manufacturing steps of textile chemical processing, enzymes are using for implementations of the green technology to meet up the challenge of fourth industrial revolution. In this category, amylases, peroxidase used for desizing and bleaching, cellulase activates for bio polishing and denim finishing. This chapter summarizes the current developments of enzyme technology and highlights the environment-friendly and sustainable enzymatic textile processing in the textile industry

Physiochemical, Optical and Biological Activity of Chitosan-Chromone Derivative for Biomedical Applications

This paper describes the physiochemical, optical and biological activity of chitosan-chromone derivative. The chitosan-chromone derivative gels were prepared by reacting chitosan with chromone-3-carbaldehyde, followed by solvent exchange, filtration and drying by evaporation. The identity of Schiff base was confirmed by UV-Vis absorption spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The chitosan-chromone derivative was evaluated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photoluminescence (PL) and circular dichroism (CD). The CD spectrum showed the chitosan-chromone derivative had a secondary helical structure. Microbiological screening results demonstrated the chitosan-chromone derivative had antimicrobial activity against Escherichia coli bacteria. The chitosan-chromone derivative did not have any adverse effect on the cellular proliferation of mouse embryonic fibroblasts (MEF) and did not lead to cellular toxicity in MEFs. These results suggest that the chitosan-chromone derivative gels may open a new perspective in biomedical applications

Dyeing of Polyester with 4-Fluorosulfonylphenylazo-5-pyrazolone Disperse Dyes and Application of Environment-Friendly Aftertreatment for Their High Color Fastness

Dyeing and fastness properties of a series of 4-fluorosulfonylphenylazo-5-pyrazolone dyes on polyester were investigated in this study. The 4-nitrophenylazo-5-pyrazolone dyes were also synthesized to compare their dyeing and fastness properties on polyester with those of fluorosulfonyl-substituted analogues. The substantivity of 4-arylazo-5-pyrazolone derivatives containing a p-fluorosulfonyl group in the diazo component was lower than that of their nitro analogues which have a higher extinction coefficient and higher affinity because of the polar nitro group. They showed relatively hypsochromic color and lower chroma on polyester compared with their nitro analogues because of the relatively weaker electron-accepting power of the fluorosulfonyl group compared to the nitro group. Disperse dyeing of polyester with 4-fluorosulfonylphenylazo-5-pyrazolone disperse dyes achieved high color fastness and reduces the adverse environmental impact of the dyeing process by providing the option of performing alkali clearing instead of reductive clearing, which has high biological oxygen demand when discharged into the dyeing effluent and generates carcinogenic aromatic amines

Synthesis and Application of N-methylphthalimidylazo Disperse Dyes to Cellulose Diacetate for High Wash Fastness

Cellulose diacetate fibers were prepared from cellulosic biomass with high α-cellulose contents such as purified cotton linters and wood pulps. Cellulose diacetate fibers are sensitive to alkaline solution, which causes hydrolysis of the acetate ester to hydroxyl groups, especially at high temperatures. Thus, the low alkali-resistance of cellulose acetate fibers makes it difficult to achieve high wash fastness by restricting the application of intense after-treatment, such as reduction clearing. A series of N-methylphthalimide-based high-washable azo disperse dyes were synthesized and their dyeing and fastness properties on cellulose diacetate fabrics were investigated. From the overall results obtained in this study, N-methylphthalimidylazo disperse dyes are expected to be a desirable alternative to high value-added dyes that can be used for high color fastness dyeing of cellulose diacetate with a minimal discharge of wastewater during washing process