Preparation And Properties Of Poly (Methyl Methacrylate) Particles Incorporating A Chemical Sunscreen Agent

In this work,poly(methyl methacrylate)-ethylhexyl salicylate(PMMA-EHS)particles were prepared via emulsion polymerization,MMA was used as wall material,EHS was used as core material.Single factor optimization experiment was used to investigate the effection of the monomer ratio,the amount of emulsifier,homogeneous speed,temperature,stirring speed,the initiator concentration on size,loading content and morphology.On the basis of single factor optimization experiment,orthogonal experiments was used to further optimizing the preparation conditions.Transmission electron microscopy(TEM),Scanning electron microscopy(SEM),Fourier transformation infrared spectroscopy(FT-IR),thermal gravimetric analysis(TGA),Malvern Zetasizer Nano ZS,Ultraviolet spectrophotometer,optical microscopy were used to investigate properties of the particles.The results show that a better preparation condition is EHS:MMA 2:1,emulsifier 6g,50?,initiator concentration1.5%,homogeneous speed 19000 rpm,stirring speed 350 rpm,the average particle size is500 nm,spherical morphology as TEM,SEM observation,the embedding rate is 60.6%,the embedding efficiency 90.9%,SPF10.21,compared with free EHS containing sunscreen cream,the sun protection factor(SPF)value of PMMA-EHS particle contained sunscreen cream increased by about 57.2 %,which indicated a significant enhancement of UV protection ability by encapsulating EHS in PMMA.Encapsulating the chemical sunscreen agent EHS in PMMA particles greatly reduced the skin irritation induced by direct contacting with skin.In addition,PMMA-EHS particles were proved to be no leakage,exhibited good stableility and have synergy effect in application.