| As an anionic amino acid surfactant with the advantages of good mildness,cleanliness and environmental friendliness,sodium lauroyl glutamate has a good application prospect in personal care and home care products.The difficulty of solubility and thickening of sodium lauryl glutamate in aqueous solution has led to some limitations in its practical application.To address these problems,this paper firstly investigates the effect of counter ions on the properties of sodium lauroyl glutamate.Secondly,different amphoteric surfactants were compounded with lauryl glutamate to solubilize the lauryl glutamate by forming mixed micelles,and then the phase state of the compounded system was investigated with concentration and ratio,and the different phase states were characterized.Finally,the generation of worm micelles in the complexed system was verified and the effect of concentration on worm micelles was investigated.In addition,the irritation and foam properties of the blended system were characterized.The main investigations were as follows:(1)The interfacial properties of sodium lauroyl glutamate were used as an entry point to investigate the effects of the type and addition of counter ions on the critical micelle concentration,foam properties,emulsification properties,and irritation of sodium lauroyl glutamate.It was found that the counter ions could reduce the critical micelle concentration of sodium lauroyl glutamate and enhance its foam performance and reduce its emulsification performance when the addition amount did not exceed 10% of sodium lauroyl glutamate,but had no effect on the irritation.The effect of sodium ion on sodium lauroyl glutamate is more significant than that of potassium ion,which is also a monovalent counter ion.(2)The counter ions could not improve the viscosity of sodium lauroyl glutamate solution,in order to be able to improve the viscosity of the system,the amphoteric surfactants were selected to play the role of counter ions in the system as well.Betaine,amine oxide and imidazoline surfactants were selected to compound with sodium lauroyl glutamate in different proportions,and the viscosity was observed by appearance,conductivity test,polarized light microscope observation,viscosity The phase states of the mixed systems in different states were determined by means of appearance observation,conductivity test,polarized microscope observation,viscosity test,etc.,and ternary phase diagrams were drawn.Through the tests,the system formed by mixing sodium lauroyl glutamate with lauryl propyl hydroxysulfonyl betaine showed a significant viscoelastic state at the concentration between 30% and 40%,and the percentage of sodium lauroyl glutamate was 0.1~0.5,and it was possible that worm micelles were formed.(3)The rheological properties of the viscoelastic system formed by sodium lauroyl glutamate/lauroyl propyl hydroxysulfonyl betaine compounding were tested,and the system was found to have the characteristics of shear thinning and pseudoplastic fluid,and the growth trend of the viscosity of the system with concentration was investigated,which are the characteristics of worm micelles.Then the generation of worm micelles was verified by cryotransmission electron microscopy.Finally,the foam performance and irritation tests demonstrated that the worm micelles could improve the stability of the foam formed without increasing the irritation of the system. |
