Light Diffusion Powder Material - Silicone Microsphere Powder (Polymethylsilsesquioxane)

Polymethylsilsesquioxane is an important type of nano-hybrid material that integrates the properties of inorganic and organic materials. At the same time, the organic group structure in the molecule is easy to modify and functionalize, so it is widely used in photoluminescent materials, photonic crystals, adsorption materials, flame retardant materials, functional coatings, etc.

SiO2 aerogel made from methyltrimethoxysilane (MTMS) and methyltriethoxysilane (MTES) is flexible and hydrophobic due to the presence of non-polar methyl end groups in the three-dimensional porous network structure. The basic structural formula is CH3SiO1.5, so it is also called methylsilsesquioxane.

The reaction process of MTES to prepare polymethylsilsesquioxane is as follows:

The method of preparing organosilicon using methyltriethoxysilane produces ethanol that is more environmentally friendly than methanol produced by MTMS.

According to the selected silicon source, the R group can be modified to obtain siloxanes of different groups to prepare silicon micropowders with different functions. In water-based light diffusion coatings, organosilicon powders with better hydrophilicity should be selected, while organosilicon containing hydrophobic groups such as methyl groups is not conducive to its dispersion in water-based coatings, thereby affecting the light diffusion effect of the coating. At the same time, the dispersibility of the powder seriously affects the uniformity of the coating, and has a greater impact on the uniformity of light diffusion.

Organosilicon micropowders of different groups have different refractive indices, and are also different in product design. The greater the difference between the refractive index of the powder and the refractive index of the resin, the better the haze effect of the coating prepared at a low mass fraction, the higher the light transmittance, and the lower the loss of light.

At present, most of the R groups on the surface of the organic silicon micropowder produced in China are hydrophobic methyl and vinyl groups, which are stable in storage and relatively easy to prepare. However, for the hydrophilic microsphere powder, it is not easy to control the particle size of the powder due to the surface groups, and it is easy to agglomerate, so there are fewer products on the market. Most of the organic silicon microsphere powder containing methyl is mainly used to prepare light diffusion plates, such as PC boards, lampshades, etc., which can be molded in one time to obtain the required light diffusion effect.