Whiteness improvement of citric acid crosslinked cotton fabrics by sodium hydrosulfite bleaching

ABSTRACT

Citric acid (CA)-crosslinked cotton fabrics show a yellowish appearance because CA forms C=C bonds during the heating process. The whiteness was improved by sodium hydrosulfite (Na₂S₂O₄), which was confirmed by the Fourier transform infrared spectra. The computational calculations showed that Na₂S₂O₄ is more effective than H₂O₂ when the system of CA-treated cotton is bleached. Based on the reaction mechanism of Na₂S₂O₄ bleaching, the influences of Na₂S₂O₄ concentration, bleaching temperature, bleaching time, bleaching pH on whiteness, and wrinkle recovery angle were investigated. The optional bleaching condition was 14% Na₂S₂O₄ and sodium pyrophosphate (Na₄P₂O₇), 70°C, and 40 minutes. The effect on the performance of fabrics bleached with Na₂S₂O₄ was similar to the effect of non-formaldehyde crosslinker 1,2,3,4-butane tetracarboxylic acid (BTCA) and the widely used crosslinker dimethyloldihydroxyethyleneurea-treated cotton. CA-treated cotton bleached by Na₂S₂O₄ showed a good persistence of bleaching effect.

摘要

柠檬酸 (CA) 交联棉织物在加热过程中形成C=C键, 出现泛黄现象. 通过傅立叶变换红外光谱证实, 连二亚硫酸钠 (Na₂S₂O₄) 提高了白度. 计算结果表明, 在柠檬酸免烫棉织物漂白过程中, Na₂S₂O₄比H₂O₂更有效. 从Na₂S₂O₄漂白反应机理出发, 研究了Na₂S₂O₄浓度, 漂白温度, 漂白时间和漂白pH值对白度和折皱回复角的影响. 最佳漂白条件为14%Na₂S₂O₄和焦磷酸钠 (Na₄P₂O₇), 70°C40分钟. Na₂S₂O₄漂白后织物的性能类似于无甲醛交联剂1,2,3,4-丁烷四羧酸 (BTCA) 和广泛使用的交联剂 (DMDHEU) 处理过的棉织物. CA免烫的棉织物经Na₂S₂O₄漂白后, 具有良好的持久漂白效果.

KEYWORDS:

• Citric acid
• durable press finishing
• sodium hydrosulfite
• bleaching
• whiteness

关键词:

• 关键词: 柠檬酸
• 经久耐用的压榨整理
• 连二亚硫酸钠
• 漂白
• 白度

Acknowledgments

This work was financially supported by the Inner Mongolia University of Technology Undergraduate Training Program for Innovation and Entrepreneurship (2020183007) and Ph.D. Programs Foundation of Inner Mongolia University of Technology (DC2000001239).

Disclosure statement

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

Additional information

Funding

This work was supported by the Inner Mongolia University of Technology Undergraduate Training Program for Innovation and Entrepreneurship [2020183007]; Ph.D. Programs Foundation of Inner Mongolia University of Technology [DC2000001239]; the Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region [No. NJZY22392] .