The Principle Of Reaction Between Surfactin And Cotton Fabric And Its Application In The Pretreatment Of Cotton Fabric

With the development of biotechnology and the improvement of people's awareness of environment protection,the application of biological surfactants in pharmaceutic a l,environment protection,food processing,oil extraction,textile detergent and cosmetic research and development has gained more and more attention.Compared with synthetic surfactants,biological surfactants can reduce the surface tension of liquid and improve the performance of emulsifying and dispersing.It also has some special advantages,such as biodegradable,no damage to the environment,non-toxic or low toxicity,low stimulation to organisms and so on.Lipopeptide biological surfactants are particularly famous because of their unique structure.Bacil us subtilis surfactin is a representative category of lipopeptide biological surfactants,known as one of the most efficient biological surfactants.Studies have shown that surfactin has high surface activity,excel ent emulsification,dispersion,wetting properties,high temperature resistance,salinity and other properties,which can be fermented from industrial waste.The thesis mainly consists six parts.The first part summarizes the properties and applicatio n status of surfactin,and il ustrates the research purpose and significance of this subject.In the second part,the adsorption kinetics and adsorption thermodynamics between surfactin and cotton fabric were indicated,and the result shows the adsorption of the surfactin on cotton fabric was in accordance with the quasi-second adsorption kinetics equation.The thermodyna mic curve indicates that the adsorption process belongs to the Langmuir adsorption model,which means the adsorption of surfactin on cotton fabric adsorbed as single molecular layer and belonged to spontaneous heat exothermic reaction.The third part we tested the emulsifica t io n and wetting ability of the surfactin,SDS and TX-100,as well as the mixture of the Bacillus subtilis lipids and SDS,surfactin and TX-100 in different proportions.The result shows that adding a small amount of surfactin can improve the wetting ability of the solution dramatica lly.The wetting ability of the mixture of surfactin and SDS solution was stronger than that of the single SDS solution,and it increases with the increase of the proportion of surfactin.When mix the surfactin with TX-100 at the ratio of 1:3,the wetting ability of the solution was well.In the fourth part,we used surfactin alone and mixed it with the other two commercial surfactants,and changed the dosage and process temperature.By testing the whiteness and wettability of the treated fabric,we could evaluate the performance of the surfactin as a scouring auxiliary.It was found that surfactin has comparable performance compared with the other commercia l surfactants.When mixing the surfactin with SDS and TX-100,the scoured fabrics have better wettability than it applied alone.In the fifth part,the surfactin was used as bleaching agent in the process of oxygen bleaching,and it could meet the requirements of bleaching process even it was used singly,however,and it performed better when used as mixture with SDS or TX-100.In the last part,the surfactin was used as bleaching surfactant in TAED low temperature system.When the process temperature is 70oC,the bleached fabric gain satisfying result with the process applying surfactin singly.However,only by compounding surfactin with other commercial surfactant,can we get the satisfying bleached fabrics at lower bleaching temperature(60oC).In addition,the change of bleaching agent will not directly affect the whiteness of bleached fabric,the whiteness is mainly determained by bleaching temperature.