Study On Preparation And Properties Of Nano-silica Loaded Sunscreen

Diethylamino hydroxybenzoyl hexyl benzoate?DHHB?is a sunscreen agent in UVA area.It has good photochemical stability and good compatibility with other oils.DHHB can be widely used in cosmetics as a sunscreen agent.Ethyl hexyl methoxycinnamate?OMC?is a sunscreen agent in UVB area.It has no irritation to skin and good safety.However,DHHB and OMC directly act on skin for a long time and may cause photosensitivity,photodegradation,skin cancer and other adverse reactions when exposed to ultraviolet radiation.nano-silica is an amorphous white powder functional material with inorganic inert material,non-toxic,odorless,small particle size,good transparency,strong ability to reflect ultraviolet rays,no color change,no decomposition reaction,good stability and high compatibility with human body.microspheres nano-silica?MSNs?is a new material with unique structure,which make MSNs have larger specific surface area and lower density.Therefore,their optical properties,permeability,adsorption properties,loading and sustained release properties are better.They are widely used in many fields,such as environment,medicine,catalysis,microreactor,etc.In this paper,nano-silica was used as wall material to load UVB sunscreen OMC,MSNs were prepared as wall material to load UVA sunscreen DHHB.The main contents of this study are as follows:to reduce the skin damage caused by sunscreen,and to improve its ability to protect against ultraviolet radiation.?1?in this paper,MSNs was prepared by soft template method.In ethanol water system,CTAB was used as template,hexane as porogen,TEOS as silicon source and ammonia as catalyst.Silica was coated on template surface by sol gel reaction,then MSNs was removed by calcining at 550?.The structure of MSNs was characterized by SEM,TEM,FT-IR,TG-DTA and BET.The effects of CTAB,n-hexane,alcohol/water volume ratio,TEOS,NH₃ and reaction time on MSNs were investigated.?2?In this paper,DHHB@MSNs was prepared by loading DHHB by impregnation method and rotary evaporation method.The results of SEM,TEM,FT-IR,TG-DTA and BET analysis show that DHHB@MSNs has uniform particle size distribution and smooth spherical morphology.The adsorption-desorption curve of DHHB@MSNs is Langmuir IV isotherm with obvious H3 hysteresis loop.The specific surface area of DHHB@MSNs is 24.90 m²/g.Compared with MSNs,the specific surface area of MSNs is 496.2 m²/g significantly reduce.The mesoporous channel and internal cavity structure of MSNs successfully loads DHHB.The effects of MSNs prepared under different reaction conditions on the loading capacity and stability of DHHB were also investigated.Among them,HCTAB1,H-hexane 5,HTEOS3 and HT1 have higher loading capacity.Its loading capacity is 48.78%,32.12%,41.04%,27.43%respectively,and have good stability,which meets the requirements of industrial production.?3?in this paper,the sol gel method was used in the alcohol water system,and CTAB was used as surfactant.Its lipophilic group contacts OMC and hydrophilic grou contacts water to form a spherical micelle structure.TEOS was used as the silicon source and ammonia as catalyst.The sol gel reaction was used to form the core shell structure on the surface of the micelle,which means that OMC@SiO₂ was obtained.The results of SEM,TEM and FT-IR analysis show that the surface of OMC@SiO₂ is spherical core-shell structure with regular and smooth structure,uniform particle size distribution,size between 650-670 nm and good dispersion.The effects of OMC@SiO₂ prepared under different reaction conditions on the encapsulation rate,loading capacity and stability of OMC were investigated.The encapsulation rates of MOMC1,OCTAB5,O alcohol/water 6,OTEOS 6 and ONH₃5 respectively.are 98.76%,93.93%,98.45%,98.45%and 98.96%,The values of MOMC6,OCTAB2,O alcohol/water 6,OTOSE3 and ONH₃5 respectively.are 19.08%,19.08%,11.26%,11.17%,5 972%with good stability.