Dyeing of Cochineal Natural Dye on Cotton Fabrics Treated with Oxidant and Chitosan

ABSTRACT

Cotton fabrics were modified through an oxidation of the fabric with hydrogen peroxide followed by chitosan to improve their dyeability toward cochineal natural dye. Comprehensive studies were conducted on these fabrics to select chitosan modification process and assess their dyeability to cochineal in the ethanol-water system. The scanning electron micrograph showed the chitosan was deposited on the surface of cotton fiber. The infrared spectrum revealed the interaction between chitosan and cellulose further. Thermal gravity analysis showed the treatment produced little effect on the thermal stability of the cotton fabric. Treating cotton with 15 g/L chitosan and baking at 130°C offered higher cochineal adsorption. Dyeing with increased time and at elevated temperatures resulted in higher dye uptake. The ratio of ethanol and water had obvious effects on solution polarity and when the proportion of ethanol and water was 9:1, cochineal adsorption reached maximum value. pH value had complex effects on K/S value and pH 7 yielded the highest color strength. Dyeing kinetics curves indicated that with the increase of the dyeing temperature, dye diffusion coefficient increased and half dyeing time decreased. The washing and rubbing fastness of the treated cotton fabrics were all improved and rated above grade 3.

摘要

以棉织物为原料, 经双氧水氧化、壳聚糖氧化改性, 提高其对胭脂虫天然染料的染色性能。对这些织物进行了综合研究, 选择壳聚糖改性工艺, 并对其在乙醇-水体系中对胭脂虫的可染性进行了评价. 扫描电镜照片表明, 壳聚糖沉积在棉纤维表面. 红外光谱进一步揭示了壳聚糖与纤维素的相互作用. 热重分析表明, 处理对棉织物的热稳定性影响不大. 用15g/L壳聚糖处理棉花, 并在130℃烘烤, 可提供更高的胭脂虫吸附。随着染色时间的延长和温度的升高, 染料的吸收率也随之提高. 乙醇和水的比例对溶液极性有明显影响, 当乙醇和水的比例为9:1时, 胭脂虫的吸附达到最大值. pH值对K/S值有复杂的影响, pH7的显色强度最高. 染色动力学曲线表明, 随着染色温度的升高, 染料扩散系数增大, 半染色时间缩短. 处理后的棉织物的洗涤和摩擦牢度均得到了提高, 均在3级以上.

KEYWORDS:

• Cochineal
• natural dye
• cotton fabric
• chitosan
• dyeing

关键词:

• 胭脂虫
• 天然染料
• 棉织物
• 壳聚糖
• 染色

Acknowledgments

The authors greatly appreciate for the financial support by Education Department of Hubei Modern Textile Engineering and Technology Research Center of Wuhan Textile University and National Key R&D Program of China (National Key R&D Program of Chin).

Additional information

Notes on contributors

Guizhen Ke

Guizhen Ke is associate professor of Wuhan Textile Universtity, researches focus on functional textile material and natural dye.

Kundi Zhu

Kundi Zhu is a graduate student of Wuhan Textile Universtity, majoring in textile material and engneering.

Mofasser Haque Chowdhury

Mofasser Haque Chowdhury is graduate student of Wuhan Textile Universtity, majoring in textile material and engneering.