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Desizing
Desizing is the process of removing the size material from warp yarns after a textile fabric is woven. Sizing agents Sizing agents are selected on the basis of type of fabric, environmental friendliness, ease of removal, cost considerations, effluent treatment, etc. Natural sizing agents Natural sizing agents are based on natural substances and their derivatives: * Starch and starch derivatives: native starch, degradation starch, chemically modified starch products * Cellulosic derivatives: carboxymethylcellulose (CMC), methylcellulose, oxyethylcellulose * Protein-based starches: glue, gelatin, albumen Synthetic sizing agents * Polyacrylates * Modified polyesters * Polyvinyl alcohols (PVA) * Styrene/maleic acid copolymers Desizing processes Desizing, irrespective of what the desizing agent is, involves impregnation of the fabric with the desizing agent, allowing the desizing agent to degrade or solubilise the size material, and finally to wash out the degradation product ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Persulfate
Sodium persulfate is the inorganic compound with the formula Na2 S2 O8. It is the sodium salt of peroxydisulfuric acid, H2S2O8, an oxidizing agent. It is a white solid that dissolves in water. It is almost non-hygroscopic and has good shelf-life. Production The salt is prepared by the electrolytic oxidation of sodium bisulfate: :2 NaHSO4 → Na2S2O8 + H2 Oxidation is conducted at a platinum anode. In this way about 165,000 tons were produced in 2005. The standard redox potential of sodium persulfate into hydrogen sulfate is 2.1 V, which is higher than that of hydrogen peroxide (1.8 V) but lower than ozone (2.2 V). The sulfate radical formed in situ has a standard electrode potential of 2.7 V. However, there are a few drawbacks in utilizing platinum anodes to produce the salts; the manufacturing process is inefficient due to oxygen evolution and the product could contain contaminants coming from platinum corrosion (mainly due to extremely oxidizing nature of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |