Impact of Hydrogen Peroxide Concentration during Cooking on the Physical Properties of Tasar Silk

Tasar silk, a prominent variety of wild silk, is valued for its strength, luster, and eco-friendly attributes. However, the efficiency of cocoon processing and the quality of the resultant yarn are highly dependent on the cocoon cooking method. Traditional cooking practices often rely on alkaline agents, which can be environmentally harmful and may compromise fiber quality. In response, hydrogen peroxide (H₂O₂), a milder and eco-friendly oxidizing agent, was explored in this study to evaluate its effect on the cooking performance and tensile properties of Daba and Raily Tasar cocoons. The cocoons were cooked using a constant concentration of sodium carbonate and sodium silicate (4 g/L each), while the H₂O₂ concentration was varied at 5, 10, and 15 cc/L. The study revealed that Daba cocoons exhibited a decline in cooking efficiency and reeling yield with increasing peroxide concentration, alongside a rise in overcooked and burst cocoons—suggesting fiber degradation due to excessive oxidation. Conversely, Raily cocoons showed improved reeling performance and reduced hard cocoons with higher peroxide levels, indicating their requirement for stronger oxidative conditions. Linear density analysis showed no consistent pattern with H₂O₂ concentration, confirming that yarn thickness was primarily influenced by reeling operations. Tensile testing indicated a decrease in tenacity and an increase in elongation with rising peroxide concentrations. ANOVA results confirmed that H₂O₂ concentration significantly affected tenacity and elongation in Daba yarns and elongation in Raily yarns, while tenacity in Raily yarns remained statistically unaffected. Overall, the findings emphasized the need for cocoon-specific optimization of oxidative treatment to balance reeling efficiency, yarn strength, and sustainability in Tasar silk processing.