UV AND RHEOPECTIC BEHAVIOR OF POLYSILOXANE-CLAY HYBRID NANOCOMPOSITES FOR USES IN SUNSCREEN PRODUCTS

摘要

The rheology and UV absorbance of clay/polysiloxane hybrid nanocomposites were studied in order to determine their effectiveness as a potential sunscreen gel. The nanocomposites were synthesized by hydrosilylation reaction between polymethylhydrosiloxane (PMHS) and vinyl terminated polydimethylsiloxane, (PDMS), and inhibited with sodium hydroxide (NaOH). Trimethylsiloxy terminated and silanol terminated PDMS were both used as solvents. They were also used to convert the reacted products into gels. An attempt was made to exfoliate the clay platelets in order to improve the filler dispersion in the PDMS matrix. Since this study also analyzed the suitability of use of these products as sunscreen in skin care, where moisture and wear resistance are important, the rheology of the gels was also studied. UV/ visible spectroscopy results revealed that the UV absorbing intensity of all hydrosilylated nanocomposites increased compared to neat PDMS. The higher UV/visible absorbance intensity of the hydrosilylated nanocomposites gels is believed to be the result of improved particle dispersion. Viscosity measurements showed that the viscosity of the nanocomposite gels varied with varying filler concentration.