Dyeing of Silk through Iron Ion-Induced Formation of Hydrophobic Lignin Coatings

ABSTRACT

There is a continuous demand for a specific type of Chinese silk fabric, which is one of China’s national intangible cultural heritage items called Xiang-Yun-Sha. Xiang-Yun-Sha is silk fabric dyed using the vegetable dyes from a yam and the mud from the Pearl Delta River. The ingenious and sophisticated dyeing process inspires us to explore new dyes for silk. Through learning from the traditional mud dyeing process of Xiang-Yun-Sha, especially the contents of the mud, lignin and iron species are recognized as key factors. Yet little attention has been dedicated to lignin as a dye despite its wide applications. In this study, the feasibility of using lignin to dye silk is investigated using sodium lignosulfonate and alkaline lignin as model systems. Thanks to their advantageous polyphenolic features, such as stacking tendency and ability to form stable complexes with iron ions, lignin-related compounds show excellent performance in serving as dyes by themselves, as well as protective coatings for other dyes; the dyed silk fabric could inherit anti-ultraviolet property from lignin. Considering that iron is inexpensive and that leftover lignin is a vastly underutilized biomass resource, this study offers a promising strategy to exploit the enormous potential of these naturally occurring materials by developing high value-added products.

摘要

香云纱，中国国家级非物质文化遗产，是一种用纯植物染料薯莨汁和珠江三角洲地区特有的河涌塘泥染色而成的丝绸. 香云纱独特而巧妙的染色工艺为我们探索丝绸的新染料提供了丰富的经验. 通过借鉴香云沙的染色工艺, 特别是河涌塘泥的重要组分, 认为木质素和铁起到关键作用. 虽然木质素已被广泛应用, 但它自身作为一种染料却很少受到关注. 受此启发，本研究以木质素磺酸钠和碱木质素为模型体系, 研究了木质素及其衍生物用于丝绸染色的可行性. 由于其多酚结构, 具有较强的堆积倾向和与铁离子形成稳定配位化合物的能力, 木质素在自身作为染料以及作为其他染料的保护涂层方面表现出优异的性能; 染色后的真丝织物可以保留木质素的抗紫外线性能. 考虑到铁在地球上储量丰富价格低廉, 木质素是一种未充分有效利用的天然可再生资源, 本研究也通过开发高附加值产品，为合理开发利用这些自然资源的巨大潜力提供了一种很有前景的新策略.

KEYWORDS:

• Silk
• lignin
• iron
• dyeing
• coating
• hydrophobic

关键词:

• 蚕丝
• 木质素
• 铁
• 染色
• 涂层
• 疏水

Highlights

• a new method with a high commercial potential through learning from Xiang-Yun-Sha

• lignin and iron species as sustainable and controllable ingredients for dyeing silk

• a promising strategy for converting underutilized lignin into high value-added products

Acknowledgments

The authors thank the National Center for Protein Sciences at Peking University in Beijing, China, for assisting with the ITC tests and Dr. Hui Li for helping with ITC tests on guaiacol. The authors also thank Dr. Baochang Sun for kind assistance on potentiometric titration experiments. This work was supported by the National Natural Science Foundation of China under Grant [number: 21972009].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15440478.2022.2101580

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [21972009].