Preparation Of POSS Modified Wollastonite And Its Application In UV Curable Coatings

The encapsulated particles are composed of shell particles and core particles,which endow the core particles with special properties that the shell particles do not have,and make the core particles functionalize.Many papers around the world show that hydrophilic silica particles and wollastonite are usually orderly compounded,and it is important to explore a hydrophobic material to compound with wollastonite to improve the dispersion and functionality of wollastonite.However,the traditional solid-phase mechanochemical method has poor dispersibility,limited performance and instability.The liquid-phase mechanochemical method of high-pressure homogenizer can solve the problems of solid-phase mechanochemical method.Therefore,the preparation of wollastonite composite granular materials by high-pressure homogenizer is of certain scientific research and practical significance.Ultraviolet curing coatings have been widely used in recent years because of their fast curing and green environmental protection.The preparation of functional coatings with modified wollastonite is a hot research topic of functional coatings,which has great development prospects and application value.In this paper,heptaphenyltrisilanol POSS was synthesized by dehydration and condensation of phenyltrimethoxysilane under alkaline conditions.The structure of the synthesized heptaphenyltrisilanol POSS was characterized by IR,¹H,¹³C and ²⁹Si NMR spectra.The wollastonite was dispersed and broken by POSS and wollastonite under the action of liquid mechanical force of high pressure homogenizer.The size change of wollastonite before and after homogenization by high-pressure homogenizer was studied by laser particle size analyzer.The effects of composition ratio,homogenization pressure,number of times,slurry concentration and other factors on the structure change of composites were studied by means of infrared spectroscopy,XRD,SEM and water contact angle.The better conditions and proportion of composites were obtained.Finally,the heptaphenyltrisilanol POSS/wollastonite composite material after optimization is introduced into the two kinds of different UV curing coating,epoxy acrylate（EA）/butyl acrylate（BA）and vinyl trimethoxysilane（VTMS）/butyl acrylate（BA）.The ultraviolet curable hybrid superhydrophobic coatings were prepared by free radical polymerization of active double bonds in the system initiated by ultraviolet light,and the Micro-Nanostructures were formed on the surface of the coatings.Infrared spectroscopy was used to study the effect of the structure of hybrid coatings on curing time,and thermogravimetric analysis was used to study the effect of composite materials on the thermal stability of hybrid coatings.Microstructure and nanostructure of composite coatings were studied by scanning electron microscopy（SEM）,contact angle instrument was used to measure and study the changes of coatings containing different content of composite materials,and finally the mechanical properties of coatings with two systems were studied.The results showed that the synthesized substance was characterized by IR,1H,13C and29Si NMR spectra.It was proved that the synthesized substance was heptaphenyltrisilanol POSS.The particle size of wollastonite before and after high-pressure homogenizer was reduced from 15.172μm to 10.097μm,and the optimum conditions for compounding with wollastonite under high-pressure homogenizer were as follows:40%compounding ratio,12MPa homogenizing pressure,4 times homogenizing and 1%slurry concentration.The optimized POSS/wollastonite composites were introduced into the UV curing coatings of vinyl trimethoxysilane（VTMS）/butyl acrylate（BA）system to form a rough composite structure during curing.When the content of the composite reaches 12%,the contact angle between the coating and water reaches 151.96,rolling angle reaches 8.56,and the hybrid coating transforms from hydrophobicity to superhydrophobicity,and the prepared coating has good mechanical properties.