Silk Dyeing with Anthocyanin Dye Extract from Melastoma malabathricum L. Fruits Using Metal Oxides and Reducing Agents to Ameliorate Photo–Fading
Abstract
Most natural dyes have poor fastness properties because of their very low affinity for fibers and susceptibility to degradation under ultraviolet (UV) light. In this project, to improve its fastness to light, the effects of inorganic UV absorbers [zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs)] and reducing agents (sodium citrate and glucose) were assessed on silk yarn treated with the dye extract from Melastoma malabathricum fruits. The ability of inorganic UV absorbers and reducing agents to protect the photo-fading of dyed silk yarn was investigated. The results revealed that the incorporation of inorganic UV absorbers and reducing agents greatly inhibited dye photo-fading on silk yarn. Colour difference (ΔE*) values of the anthocyanin dye from M. malabathricum with a treatment of TiO2 NPs, ZnO NPs doped with Fe and glucose after 24 h exposure to simulated sunlight were 16.3, 16.2, and 15.7 respectively, while the control DE* was 20.5. These results showed that the best-performing inorganic UV absorbers for this dye were TiO2 NPs and ZnO NPs doped with Fe, while glucose was better than sodium citrate. Therefore, TiO2 NPs, ZnO NPs doped with Fe and glucose are promising alternative UV retardants in silk dyeing with the dye extract from M. malabathricum.