The Improving properties of Viscose fabric by water repellent finish

Viscose as cellulosic origin, the cheapest of all cellulosic fabrics could be the best alternative. Viscose is manufactured from regenerated cellulose. In order to manufacture viscose, pulp of bamboo is treated with aqueous sodium hydroxide to form alkali cellulose. This alkali cellulose is then treated with carbon disulfide to form sodium cellulose xanthate. The xanthate is then dissolved in aqueous sodium hydroxide and allowed to depolymerize. After depolymerization, rayon fiber is produced from the ripened solution. Viscose is primarily employed in apparels, upholstery fabric, industrial clothing, and medical hygiene. Apparels, upholstery fabric, and industrial clothing segments account for key share of the viscose market. The medical hygiene segment is anticipated to expand during the forecast period. Demand for viscose fiber is anticipated to increase significantly in the near future due to the rise in global population, increase in standard of living, and growth in disposable income. Viscose is an eco-friendly product; thus, increase in awareness about eco-friendly products and decrease in production of cotton are estimated to augment the demand for viscose fiber. Viscose fabric exhibits some similar properties compared to cotton except its poor wet strength due to higher moisture regain. In this study, chemical finishes by different cross-linkers were applied to improve the wet strength of the viscose fabric. For this purpose, water repellent finishes were applied. Water repellent finish helped in reducing the molecular barrier around the individual fibres that lowered the surface tension of the fabric. It reduces the absorbency of viscose fabric hence leads to higher wet strength. Therefore, the treated viscose fabric exhibited better wet strength after applying water repellent finishes on it. Scanning electron microscope (SEM) was used to examine the surface of the fabric treated with chemicals. Tensile strength of viscose was increased 24.6%.

A Facile Approach for the Synthesis of Zinc Ferrite/Alkali Cellulose as an Effective Magnetic Photocatalyst for the Degradation of Methylene Blue in Aqueous Solution

The spinel zinc ferrite/alkali cellulose composite has been successfully fabricated as a magnetic photocatalyst and assessed for its photocatalytic activity toward the degradation of methylene blue (MB) in an aqueous solution. The Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), thermogravimetric analysis (TGA), BET, and zeta potential were used to evaluate the magnetic photocatalyst composite and investigate its adsorption mechanism. Furthermore, the adsorption behavior of the composite was studied under various conditions. The ZnFe2O4/alkali cellulose composite effectively degraded (100%) MB after 180 min at a pH of 6.5 compared to cellulose, alkali cellulose and ZnFe2O4. The regeneration of the loaded composite was studied using the alcohol/water solution and reused upon a certain variation in the efficiency after the fourth cycle. The adsorption process was found to be consistent with the pseudo-second-order kinetic model.

Possibilities for Optimization of Industrial Alkaline Steeping of Wood-Based Cellulose Fibers

Steeping of cellulosic materials in aqueous solution of NaOH is a common pre-treatment in several industrial processes for production of cellulose-based products, including viscose fibers. This study investigated whether the span of commonly applied process settings has the potential for process optimization regarding purity, yield, and degree of transformation to alkali cellulose. A hardwood kraft dissolving pulp was extracted with 17–20 wt% aq. NaOH at 40−50 °C. The regenerated residue of the pulp was characterized regarding its chemical composition, molecular structure, and cellulose conformation. Yield was shown to be favored primarily by low temperature and secondly by high alkali concentration. Purity of xylan developed inversely. Both purity of xylan and yield varied over the applied span of settings to an extent which makes case-adapted process optimization meaningful. Decreasing the steeping temperature by 2 °C increased xylan content in the residue with 0.13%-units over the whole span of applied alkali concentrations, while yield increased by 0.15%-units when extracting with 17 wt% aq. NaOH, and by 0.20%-units when extracting with 20 wt%. Moreover, the yield-favoring conditions resulted in a narrower molecular weight distribution. The degree of transformation via alkali cellulose to cellulose II, as determined with Raman spectroscopy, was found to be high at all extraction settings applied.

Influence of pulp characteristics on the properties of alkali cellulose

Alkali extraction of cellulose material is a common treatment for several industrial processes—especially the viscose process, which produces fibers for textile applications. This study investigated different generic dissolving wood pulps by means of alkali extraction (10–18 wt% aq. NaOH at 20–50 °C). The regenerated residue of the pulps was characterized for its chemical composition, molecular structure, and cellulose conformation. The investigated pulps had in common that glucan was most intensely extracted at low temperature and low concentration of aqueous alkali, xylan was most intensely extracted at high temperature and high concentration of aqueous alkali, and mannan was most intensely extracted at a concentration of aqueous alkali > 14 wtwt% at all temperatures applied. The degree of transformation via alkali cellulose to cellulose II as determined with Raman spectroscopy was found to be maximized for all pulps at high alkali concentration and temperature had no major influence. Maximum yield for all investigated pulps was found when extraction was done with 18 wt% aq. NaOH. The importance of temperature differed for the investigated pulps. The reason for the differences in extraction behavior or different absolute levels of resulting properties was found to be related to differences in the homogeneity and purity of the pulps. A conclusion of interest for industrial applications was that extracting the pulps with 18 wt% aq. NaOH led to an optimal alkalization result for yield, purity, and conversion. The steeping temperature chosen was found to be important to balance the yield and the purity of xylan-containing pulps. Graphic abstract

Production of Carboxymethyl Cellulose from Sugarcane Bagasse and Water Hycinth.

Mines in Zimbabwe are facing a challenge in acquiring carboxymethyl cellulose because at the moment it is not being produced in the country therefore, mines like ZIMPLATS which focus on platinum mining are facing high costs of importing carboxymethyl cellulose from producing countries like China (US $3500/metric tonne ) according to Alibaba. Various raw materials including plant biomass and algae have been used to produce cellulose. In this work, sugarcane bagasse and water hyacinth were used as a raw materials for cellulose extraction. Cellulose was extracted from the biomass through the elimination of lignin and hemicellulose. The preparation of CMC involves two main reactions or steps which are mercization and etherification by a slurry process. In the slurry method, cellulose is suspended in a mixture of NaOH-water-alcohol systems at 20 30 C with an excess of alcohol (ethanol or isopropanol), to ensure a good mixing efficiency. In the mercerization process, the liquid phase (water-alcohol mixture) which acts as a solvent, dissolves the NaOH and distributes it evenly to the cellulose hydroxyl groups forming alkali cellulose. Furthermore, the alkali cellulose produced is reactive towards monochloroacetate acid (MCA), which is added in the second step either as free acid, MCA or its salt, sodium monochloroacetate acid (NaMCA) to form carboxymethyl cellulose ethers. The results indicated that the optimum concentration of sodium hydroxide for alkalization to occur is 30% .The carboxymethylation process of cellulose was confirmed using potentiometric back titration and Fourier Transform Infrared Spectroscopy.The percentage yield was 85,2%.