Abstract： In this study, a series of novel silane coupling agent (SCA) was employed as a modifier for silica particles in the aqueous sol. thus hydrophilic silica particles were converted into hydrophobic ones.The modified silica particles were then added into the epoxy resin, the influences of different SCA and their amount on the surface modification of silica particles was investigated, including the rheological behavior of the silica/isopropanol sol, the dispersion of silica particles in epoxy matrix, and the strengthening and toughening effect of the modified silica particles on epoxy adhesives. The results of Infrared spectrometry (IR) and Thermal Gravity Analysis (TGA) confirmed that a considerable amount of SCA molecules were grafted onto the surface of silica particles. Furthermore, the dispersion of silica particles in isopropanol sol was investigated by Dynamic Lightening Scattering (DLS), showing that a homogenous dispersion was obtained by SCA modification.The modified silica particles were employed as a modifier for the epoxy adhesives. Transmission Electron Microscopy (TEM) was used to observe the dispersion of silica in epoxy adhesives. It shows GPPTES modified silica helped silica particles reached a homogenous dispersion in epoxy resin. Mechanical properties of silica filled epoxy adhesives were studied. Shear strength and uneven tear strength were both increased by addition of treated silica, but deceased by addition of untreated one.
