Chemical surface modification of precipitated silica nanoparticles using 3-glycidoxypropyltrimethoxysilane by deposition from aqueous alcohol

In this research, the amorphous and hydrophilic silica nanoparticles prepared by precipitation method, were surface modified using a silane coupling agent (3-glycidoxypropyltrimethoxysilane, GPTMS). High surface density of OH- groups on the surface of precipitated silica is leading to hydrophilic nature of the particles. It causes agglomerate the nanoparticles and effects on their dispersion in the polymer matrix.Silane treatment with a silane coupling agent such as GPTMS, is leading to replacement of hydroxyl groups with an organofunctional group (glycidox) and changing the surface chemical behavior of silica nanoparticles. The morphology of nanoparticles was evaluated before and after silane treatment using the transmission electron microscope (TEM). Fourier transform infrared spectrophotometer (FTIR) was used to evaluate functional groups and ensure of their attaching on the surface of nanoparticles. Also, dispersivity of nanoparticles through the three organic solvents, before and after modifying, was investigated by light transmittance (LT) method. The results showed that using the calculated theoretical amount of GPTMS for covering a monolayer of organofunctional groups around the nanoparticles, agglomeration effectively broke up and dispersivity of nanoparticles improved in organic solvents.

Keywords:

Silica nanoparticles , silane coupling agent:3-glycidoxypropyltrimethoxysilane:Surface modification