Study On The Preparation And Properties Of Silk Protein Based Surfactant

Proteins composed of polar and nonpolar amino acid connected by peptide bonds, should be a kind of ideal surfactants. However, because of particular structure of protein and coiling fold of polypeptide chain, most of proteins can't show their surface active properties as the nonpolar groups of proteins are covered in the compact and steady protein molecules. We use salt dissolving, hydrolysis, chemical modification method to study the surface properties of silk protein. Conclusion is listed below :1.This paper established the preparation technology of the sericin and silk fibroin. The best optimized conditions of the sericin: V(water):V(silk waste)=90:1, ultrasonic time 15min, Temperature 95℃, temperature time 25min. The silk sericin protein was prepared using the freeze-drying technology. The best optimized conditions of the silk fibroin protein: V(CaCl2, 5mol/L):V(silk waste)=8:1, the salt dissolve time 15min, desalting time(pressure) 6h. The silk fibroin protein was prepared using the freeze-drying technology. SDS-PAGE gel electrophoresis showed that the molecular weight of the silk sericin protein is continuous and the molecular weight of the silk fibroin protein is single. silk sericin protein and the silk fibroin protein showed different degree of surface activity.2.Silk protein hydrolysis was studied in this paper under the condition of external force. The best technological conditions: hydrolysis temperature 120℃(0.2MPa), the concentration of sulphuric acid 26%, time 20min, the liquid-solid ratio110:1, yield 99.99%.3 . Silk hydrolysate active surface properties:CMC0.6g/L,γ29.5 mN/m, the emulsification 90%, emulsion stability 85%, foam ability 81%, foam stability 85%, HLB 11, Wetting time 74.5s, detergency 55%.4.Silk protein chemical modification process: dodecanoyl chloride 3mL, composite amino acids15mL, acetone 7mL, pH12,reaction temperature55℃, reaction time 4h. The average production of N- dodecanoyl composite amino acids is 92.5% under the optimum synthesis conditions. It shows good surfactant properties. CMC0.8g/L,γ27.6.5mN/m, the emulsification 90%, emulsion stability 85%, foam ability 81%, foam stability 85%, HLB 11, Wetting time 74.5s, detergency 55%.5.We study the formation of molecular thermodynamic functions, standard of adsorption dynamics and its influencing factors.The silk protein that is prepared using the method of salt soluble is not very good in active surface properties. And the silk protein that is prepared using the method of hydrolysis has a certain increase in surface properties, but also has many defects. The silk proteins after chemical modification shows good and overall surface properties, effectively improves the surface properties of silk protein. This method provides an effective way of effectively using waste cocoons, discard silk, non-toxic, and preparing of green protein surfactant.