Preparation And Properties Of High Refractive Index Nano-hybrid Materials

With the progress of the times,materials science and technology has been developing rapidly as an important basis for the transformation of China’s strategic new industries.High refractive index materials are a class of optical functional materials that have a wide range of applications in packaging technology,imaging technology,information technology and many other fields,and they have important practical applications and are one of the key materials science technologies studied by researchers and scholars.Traditional high refractive index optical materials are generally classified into two categories,inorganic optical materials and organic optical materials,according to the type of material.For inorganic materials,although they have high refractive index,their mass is large,high price,poor impact strength and other properties are difficult to meet the needs of high-performance optical components,while organic materials have the advantages of light weight,wear resistance,impact resistance,etc.,but the refractive index is relatively low,limiting its development.Therefore,in recent years,nano-hybrid materials,which can combine the advantages of organic and inorganic materials,have received great attention.High refractive index nanohybrid materials are nanoparticles with high refractive index incorporated into polymer matrix as functional fillers.Hybrid materials have a wide range of refractive index,and the refractive index is continuously adjustable.However,the biggest challenge of organic/inorganic hybrid materials is to solve the compatibility of inorganic fillers and organic resins and to control the particle size of inorganic nanoparticles,which must be free of agglomeration and have a particle size less than one-tenth of the visible wavelength,otherwise the optical and mechanical properties of the hybrid materials will be affected.Based on the core problem of high refractive index nano-hybrid materials,high refractive index ZrO₂ nano-hybrid epoxy,high refractive index TiO₂ nano-hybrid epoxy and UV-curable high refractive index Ti hybrid organosilicon composites were synthesized by different preparation methods.Their structures,properties and application effects were also investigated.Part Ⅰ:Preparation and properties study of high refractive index ZrO₂ hybrid epoxy.A high refractive index epoxy containing S elements and fluorene structure was synthesized by a two-part method using 4,4’-dihydroxydiphenyl sulfide,9,9-bis（4-hydroxyphenyl）fluorene and epichlorohydrin as the main raw materials and used as a polymer matrix.And n-butanol zirconium was used as a precursor and 3-glycidyl ether oxypropyl trimethoxysilane（KH560）was used as a coupling agent to generate in situ ZrO₂ nanoparticles grafted with epoxy groups on the polymer matrix by a hot solvent method to finally prepare ZrO₂ nanohybrid epoxy.The structure and properties of the hybrid resins with different ZrO₂ contents were characterized and tested,and the results showed that the ZrO₂ particles were successfully synthesized in the polymer matrix and uniformly dispersed with nanoparticle size,and the hybrid materials had good optical properties,maintaining a transmittance of more than 89%in the visible range,and the refractive index of the hybrid resins increased linearly with the increase of the ZrO₂ content,and the refractive index of the ZrO₂ content at 19.33%reaches 1.739,the degradation temperature range of the hybrid resin is 260～500℃,the hybrid resin dispersion has good storage stability,no shrinkage and fracture after curing,the surface of the coating is smooth and flat,with the increase of ZrO₂ content,the pencil hardness of the hybrid resin is increased from3 H to 4 H,and the adhesion is also improved.Part Ⅱ:Preparation and performance study of high refractive index TiO₂ hybrid epoxy.A high refractive index epoxy containing S element,Br element,and fluorene structure was synthesized by a two-step method using tetrabromobisphenol a,4,4’-dihydroxydiphenyl sulfide,9,9-bis（4-hydroxyphenyl）fluorene,and epichlorohydrin as the main raw materials.The prepared epoxy contains a large number of-OH groups,which can provide reactive sites for the hybridization of inorganic nanoparticles.The TiO₂ hybrid epoxys were finally synthesized by chemically bonding TiO₂ particles to the polymer matrix through sol-gel method using n-butyl Titanate as the precursor.The structure and properties of the hybrid resins with different TiO₂contents were characterized and tested.The results showed that the TiO₂ nanoparticles did not show large-scale agglomeration and had good compatibility with the polymer and the matrix,and the TiO₂ nano-hybridized highly refractive epoxy had good optical properties with an average transmittance of over 90%in the visible range.The refractive index increases linearly with the increase of TiO₂ content,and the refractive index reaches 1.783 when the TiO₂ content is 19.98%.The degradation temperature range of the hybrid resin is 280～450°C.The hybrid resin dispersion has good storage stability,no shrinkage and fracture after curing,and the surface of the coating is smooth and flat,and the pencil hardness of the hybrid resin is increased from 3 H to 5 H with the increase of TiO₂ content,and the adhesion is also improved.Part Ⅲ:Preparation and performance study of UV-curable high-refractive-index Ti hybrid organosilicon composites.Using diphenyldimethoxysilane,KH570,phenyltrimethoxysilane and n-butyl Titanate as the main raw materials,under acidic conditions Ti hybrid silicone resin containing double bonds was synthesized by co-hydrolysis as UV-curable component A,and9,9-bis[（4-hydroxyethoxy）phenyl]fluorene and acryloyl chloride were used as main raw materials to synthesize A high-refractive-index monomer with a fluorene structure,as UV-curable component B.The two components were mixed and UV-cured to prepare a high-refractive-index Ti hybrid organosilicon composite.The structure,properties and applica Tion effects of the hybrid resins with different additions of n-butyl Titanate were characterized and tested.The results show that Ti element is mainly uniformly distributed in the structure of hybrid silicone in the form of Ti-O-Si,the hybrid silicone has a higher crosslinking density and a higher degree of condensation,and has a good visible light transmittance,the average light transmittance in the visible light wavelength range is above 90%.The refractive index of the Ti hybrid silicone with the largest amount of n-butyl Titanate is 1.7931,the degradation temperature of the silicon skeleton of the Ti hybrid silicone is 400～650°C,and the Ti hybrid silicone does not shrink or break after curing.The surface of the coating is smooth and flat.With the increase of Ti content,the pencil hardness of the hybrid resin increases from 4 H to 6H.In the LED application performance test,the light output efficiency of Ti hybrid silicone is compared with that of commercially available LED packaging materials.An increase of 18.7%.