关键词: 莨纱绸, 薯莨色素, 高碘酸钠, 色牢度, 缩合单宁

Abstract: Gambiered silk is a traditional Chinese silk fabric dyed with natural Dioscorea cirrhosa Lour. pigments and then coated with natural river mud. It is characterized by its smooth and crisp texture, along with excellent breathability and moisture permeability, making it highly favored since the Ming Dynasty. However, due to the poor adhesion of Dioscorea cirrhosa Lour. pigments, the traditional process requires multiple rounds of dyeing and sun exposure to fix the color. This not only limits production efficiency but also increases costs. With growing efforts to protect intangible cultural heritage, the cultural and economic value of Gambiered Silk has regained attention. Enhancing the production efficiency and color fastness of dyed Gambiered silk fabrics has become a crucial research topic. Inspired by the dyeing mechanisms of vat dyes, sodium periodate (NaIO4) is employed to oxidize the fabrics dyed with Dioscorea cirrhosa Lour. pigments to enhance their color fastness. This study also conducts an in-depth exploration of its oxidation mechanism, providing a scientific basis for optimizing traditional processes. In this study, Dioscorea cirrhosa Lour. pigments were first extracted and purified using Sephadex LH-20 gel chromatography. The purified pigments were then oxidized with sodium periodate, and their chemical structure changes before and after oxidation were characterized using UV, FTIR, and XPS techniques. Fabrics dyed with Dioscorea cirrhosa Lour. dye solutions were treated with different mass concentrations of NaIO4, and their color characteristics (L*a*b*) and K/S values were measured to evaluate dyeing depth and color stability. Additionally, the washing and rubbing fastness of the fabrics before and after oxidation treatment were tested to assess improvements in performance. The results show that sodium periodate oxidation treatment significantly improves the color fastness and dyeing depth of fabrics dyed with Dioscorea cirrhosa Lour. dye solutions. At a mass concentration of 40 g/L, the K/S value of the oxidized fabrics increased by approximately 52% compared to the original samples. Washing fastness improved from grade 2 to above grade 4, and rubbing fastness increased from grade 2 to grades 3–4, which meets the standard requirements outlined in GB 18401—2010 for apparel textiles. Mechanistic analysis revealed that NaIO4 oxidizes phenolic hydroxyl groups in Dioscorea cirrhosa Lour. pigments into carbonyl groups, introducing new chromophores and extending the conjugated system in the molecules, thereby enhancing color depth and stability. This study not only optimizes the production process of Gambiered silk but also offers new ideas and approaches for the application of traditional natural dyes in the modern textile industry. Future research could explore the potential impacts of oxidation treatment on other properties of Gambiered silk, so as to promote the modernization of traditional processes.

Key words: Gambiered silk, Dioscorea cirrhosa Lour. pigments, sodium periodate, color fastness, condensed tannins