Preparation And Characterization Of Organic Modified Silica Sustained-releasing Fragrance

Lavender is one of the most important ingredients in the world today.Lavender fragrance is widely used in cosmetics,daily chemicals,textiles and other fields.Embedding the fragrance by microcapsule technology can effectively prevent the volatilization of the fragrance,enhance the stability of the active substance,control the release rate of the essence,and also improve the shelf life of the fragrance products.The sol-gel method for preparing organically modified silica flavor microcapsules uses organosilane as a precursor.All the raw materials undergo hydrolysis-condensation reaction in the liquid phase,and the sol slowly polymerizes between the aged rubber particles to form a three-dimensional network structure of nanoencapsulated fragrance.In this paper,a series of organosilica nanoencapsulated lavender fragrance were prepared via sol-gel method.Silane precursor-ethylsilicate(TEOS)was modified with methyltrimethoxysilane(MTMS)to enhance the mechanical strength and compatibility of the wall material.Firstly,5 different synthesis conditions for the preparation of lavender fragrance nanocapsules by sol-gel method were investigated: reaction time,pH value,water/alcohol volume ratio,surfactant concentration and stirring speed.The optimum process conditions were as follows: reaction time of 24 h,pH of 9.5,water/alcohol volume ratio of 2:1,surfactant concentration of 25 mM,and agitation rate of 800 rpm.Under the optimal process conditions,the average particle size was 342 nm and the PDI was 0.225.The utilization rate of the fragrance in the prepared nanocapsules reached 96.36%.Secondly,the structure and properties of nano sustained-release fragrances were characterized.Scanning electron microscopy(SEM)results showed that the prepared lavender fragrance nanocapsules had a regular spherical structure,perfect dispersibility.Fourier transform infrared spectroscopy(FTIR)and thermogravimetric analysis(TG)demonstrated that organically modified silica wall materials were produced by sol-gel method.The TG results also provedthat the organically modified silica wall material significantly improved the thermal stability of the lavender fragrance.Finally,the prepared organically modified silica lavender fragrance was applied to the wallpaper and the performance of the aromatic wallpaper was characterized.Scanningelectron microscopy revealed that the nanocapsule fragrance adhered to the wallpaper fibers.The obtained aromatic wallpaper was further analyzed by gas chromatography mass spectrometry and artificial sensory evaluation.The aroma content curve of ordinary aromatic wallpaper and nano-capsule aromatic wallpaper recorded by gas chromatography-mass spectrometer showed that the sustained release time of nano-capsule aromatic wallpaper could be up to 3 months.The results of artificial sensory evaluation proved that the nano-capsule aromatic wallpaper did have a certain aroma after being placed for 90 days.