植物染料茜草的稳定性研究

Study on stability of vegetable dyestuff madder

文章采用差示扫描量热仪、热重/差热同步分析仪等热分析仪器、紫外/可见光分光光度仪详细研究了植物染料茜草的耐热稳定性、酸碱稳定性及储存稳定性,测试了茜草染色毛织物的耐热压色牢度和耐罐蒸色牢度。结果表明,茜草色素在100℃沸水中至少可以稳定2h,茜草染料可采用100℃沸水染色;茜草粉末染料中的某些化学成分有可能在145℃分解,350℃炭化;茜草染色毛织物的耐热压色牢度及耐罐蒸色牢度均达到3级以上;茜草色素酒精提取浓缩液可以在室温下保存90天以上,其水溶液在酸性条件下较稳定,但在碱性条件下不稳定,颜色有较大变化。

By differential scanning calorimetry （DSC）, synchronized thermogravimetry/differential thermal analysis （TG/DTA） and UV-Visible speetrephotometer, the investigates show that the coloring matters in madder are stable in water of 100℃ for at least 2 hours. As a result, it can be used as dye at the temperature of 100℃. Some chemical compositions in madder powder dyestuff can be decomposed at 145℃ and can be earbonised at 350℃. The color fastnesses to ironing and steaming of the dyed wool fabric with it are all above 3 grades. The concentrated liquid of the coloring matters of madder extracted with alcohol can be preserved for at least 90 days. The dye liquid of madder extracted with alcohol is stable at pH 3-7 and is unstable when its pH value is above 7.