紫胶色素的稳定性

Stability of lac pigment

为给紫胶色素在纺织品染色应用中提供理论参考,采用可见分光光度法研究天然染料紫胶色素在不同温度、pH值、金属离子、氧化剂、还原剂条件下的稳定性。结果表明:紫胶色素颜色随着溶液pH值的改变而变化;在酸性条件下温度对色素的影响较小;氧化剂、还原剂以及碱性条件对稳定性影响较大;Ca2+、Cu2+、Al3+、Fe3+、Fe2+、Zn2+、Sn2+等金属离子可与紫胶色素形成配合物,色素的颜色会发生改变,红外光谱证明紫胶亚铁离子配合物的形成。

The stability of lac pigment under different conditions such as temperature, pH value, metal ions, oxidants and reducing agents was investigated by spectrophotometric methods for the purpose of providing a theoretical basis for its utilization in dyeing of textiles. The results showed that the lac pigment color changed with the pH value of solution ; and temperature had little influence on it in acidic condition ; oxidant, reducing agent, and alkali were disadvantageous to its stability; Ca^2＋ , Cu^2＋ , Al^3＋ , Fe^3＋ , Fe^2＋ , Zn^2＋ ,Sn^2＋ could complex with lac pigment, alter the colorof pigment solution; lac-Fe^2＋ complex was confirmed by infrared absorption spectrum.