Study On The Effect Factors Of Liquid Crystallinity And The Performance Evaluation For Cosmetic Emulsions With Liquid Crystal Phase

In this thesis,cosmetic emulsions with liquid crystal phase were studied and the influence factors of liquid crystallinity were explored through investigating the stability of cosmetic emulsion,the physicochemical properties and the structure of the liquid crystalline phase.The effect of composition including the emulsifier,co-emulsifier,oil phase materials,aqueous phase materials and the preparation process on the liquid crystallinity of cosmetic emulsions was studied systematically,and the performance evaluation of the cosmetic emulsions in optimum composition was also investigated.The composition of the emulsion affected the liquid structure.Under determined conditions,adding coemulsifier Lanette O was helpful to form the liquid crystalline structure.However,the addition of coemulsifier GMS 105,GMS 205 or Lanette 22 was inhibited the formation of liquid crystalline phase.If two kinds of liquid crystal emulsifier and ordinary emulsifier were used with a proper proportion,the liquid crystal structure was found to be formed easily.In comparison,the oil-material GTCC and Lipex 102 P were contributed to the formation of liquid crystal structure,and the oil DC 200/100CS had no significant effect on the liquid structure;meanwhile,adding SILKFLO 364-NF,CRODAMOL,IPM and Squalane the liquid crystal structure became worse.For the aqueous phase materials,the K-F,glycerol and diethylene glycol were contributed to the formation of liquid crystal structures,and 1.3BG,Carbopol 941 has no obvious effect on the liquid crystal structure and with adding the PG,the liquid crystal structure became worse.The effect of preparation process on the structure of emulsion liquid crystal was also investigated.The results showed that with the prolonged emulsion time,the particle size became smaller,more uniform and compact,but the structure of liquid crystal did not change obviously.After the two emulsion process,the particle size became even smaller,more uniform and compact,and the structure of liquid crystal did not change distinctly.In the emulsion process,the smaller and more uniform and compact particles with better liquid crystal structure were observes under rapid stirring speed.On the contrary,the cooling rate had little effect on the crystal structure.The stability of the emulsion liquid crystal structure was studied too,and it was found that the liquid crystal structure was reduced as the time increased.The high temperature testing and the alternating tests can significantly reduce the liquid crystal structure,and the freezing tests had no influence on the liquid crystal structure.The performance evaluation of liquid crystal emulsion cosmetics showed that the liquid crystal emulsion was better than that of ordinary emulsion in the sense evaluation and efficacy evaluation.In the actual production process,we can consider the cost,technology and other factors,adjust the formula of liquid crystal emulsion in order to make the product to achieve better results.