Study On Surface Modification Of Silicone Microspheres And Application In Light Diffusion Materials

In this paper, LED light diffusion materials are studied in view of glare and blue light hazard in LED lighting. Polymer composite materials with good optical performance and blue light shielding property are prepared by the surface modification and functionalization of light diffusion agent in the light diffusion material and adjustment of the preparation technology and formulation.The main contents are as follows:1. Nano-Ce O2 is used to modified the surface of polysiloxane microspheres(SMS) by coprecipitation method. The research results indicate that when the mass ratio of Si and Ce is 1:1, it shows the best modification effect. The X-ray diffraction pattern shows nano-Ce O2 in the surface of SMS is cubic fluorite structure and the average particle size is 10 nm. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis indicate nano-Ce O2 and SMS is combined by Ce-O-Si bond. Uv-visible absorption spectrum analysis shows the absorption of the charge transfer transition from O 2p to Ce 4f in SMS@Ce O2 and the band ranged between 300 and 480 nm.2. The SMS@Ce O2 composite added to polycarbonate substrate as the light diffusion agent. At 0.6 wt% filler loading point, the transmittance for PC/SMS@Ce O2 is 63%, and the haze is 91%. After calcined SMS@Ce O2 at different temperature, the analysis shows that the calcination temperature has no effect on the light transmittance and haze of PC/SMS@Ce O2. But, in a certain temperature range, the transmittance of PC/SMS@Ce O2 in blue light region is reduced with the increase of calcination temperature, while increased in other visible light region. Compared the blue light shielding properties of different materials, the absorbance of PC/SMS@Ce O2 is twice as high as PC/SMS in blue light region, and the absorbance of both materials is similar in other visible light region, which shows that the SMS@Ce O2 composite has no effect on the transmittance of other visible light. These results show that using nano-Ce O2 modified SMS has no effect on the transmittance and haze of PC composites and can shield 50% of blue light of LED, which can reduce the blue light hazard of LED.3. Nano-Ti O2 is used to modified the surface of SMS by impregnation method. The research results indicate that the reaction between the Si-OH bonds on the surface of SMS and the Ti-OH bonds on the surface of Ti O2 is occurred and generated new Ti-O-Si bonds. X-ray diffraction and Uv-visible absorption spectrum analysis show that SMS@Ti O2 particles coexist of anatase and rutile, and the materials can absorb or hinder the UV light because of the existence of the rutile phase and can be benefit to the dispersion because of the existence of the anatase phase. The SMS@Ti O2 composite added to polycarbonate substrate as the light diffusion agent. The agglomeration of nano-Ti O2 does not appear in the light diffusion materials. At 0.6 wt% filler loading point, the transmittance for PC/SMS@Ti O2 is 73%, and the haze is 91%. Compared to that of PC composites physically mixed with SMS+Ti O2, the haze of the PC/ SMS@Ti O2 composites had little influence, while the transmittance was obviously enhanced, which can be increase from 55.5% of PC/SMS/Ti O2 to 70.3% of PC/SMS@Ti O2 with only 0.6 wt% filler’s loading. These results indicate that using nano-Ti O2 modified SMS has no effect on the haze and can enhance the transmittance, which solves the dispersion problem of nano-Ti O2 in PC when added in the very low amount.