The Study Of Hair Dyeing Process And Dyeing Mechanism With Tea Polyphenols

Tea resources is abundant in our country,and the tea garden area is 2.74 million hectares.The tea production is bout 1.95 million tons,and the distribution of tea area is wide,the tea production area is a total of 21 provinces and 967 counties and municipalities.Tea polyphenols,as one of the main components of tea extract,is a new antioxidant and is widely used as natural additives.It is widely applied to medicine,food processing,daily chemicals and other aspects,but the application of tea polyphenols in dyeing is unknown.In this experiment,the dyeing property of tea polyphenols has been studied:(1)Through analyzing the ultraviolet-visible spectroscopy of tea polyphenols,we find tea polyphenols characteristic absorption peak is at 275nm and make the linear relationship curve between concentration and absorbance;under different temperature,different illumination condition,the stability of tea polyphenols has been studied,the results show that the stability of tea polyphenols is better in low temperature and without uv irradiation;we discussed the dyeing methods,the pretreatment process conditions,hair dyeing conditions with mordant to the influence of hair dyeing effect and the best process condition has been obtained,the optimum pretreatment process conditions is that:the temperature was 50 ?,the time was 10 min,the pH value was 10,treating agent concentration was 5%,Zn2+ post-mordant hair dyeing optimum process conditions is that:the hair dyeing temperature was 50 ?,hair dyeing time was 40 min,dye solution pH value was 10,dye solution concentration was 10%,mordant concentration was 10%,Fe2+ post-mordant hair dyeing optimum process conditions is that:the hair dyeing temperature was 35 ?,hair dyeing time was 30 min,dye solution concentration was 8%,mordant concentration was 6%,in this experiment,the evaluation index of hair dyeing effect have the color eigenvalues,dyeing rate,water washing absorbance and tension value;we design three levels four factors and four levels five factors orthogonal experiment,and explore the hair dyeing rule of tea polyphenols,the results show that different hair dyeing conditions can affect multiple evaluation index.(2)Through exploring tea polyphenols dye desorption,adsorption kinetics and thermodynamics,we preliminarily research the natural dye dyeing mechanism of tea polyphenols.The stability experiment of tea polyphenols desorption results show that:with the increase of temperature,the concentration of tea polyphenols in solution substantially increases,but it reduces sometimes,this show that the process of tea polyphenols desorption and adsorption happened at the same time,tea polyphenols dye adsorption kinetics and thermodynamics experiments results show that:in the dyeing process of tea polyphenols,the tea polyphenols adsorption on hair conforms to level 2 dynamic model;we use the Freundlich adsorption isotherm equation and the Langmuir adsorption isotherm equation respectively to do linear fitting about related parameters in the adsorption process of tea polyphenols,and find that the Freundlich isothermal adsorption equation model can better describe the adsorption process of tea polyphenols on hair;known from the analysis of the adsorption thermodynamics data,hair adsorption tea polyphenols process is spontaneous,exothermic,entropy increase.