Effect of silica nanoparticles surface treatment on in situ polymerization of styrene–butyl acrylate latex

Abstract

In this study, silica nanoparticles were treated by γ-methacryloxypropyltrimethoxy silane (MPS), via a two-step sol–gel route. The effects of treatment conditions; such as: pH, time, silane and water amounts on the surface modification of silica nanoparticles were evaluated. MPS grafting on the surface of nanoparticles was characterized using FTIR, TGA and TEM techniques. The un-treated and MPS-treated silica nanoparticles were used for in situ preparation of silica/styrene:butyl acrylate latex nanocomposites. The synthesized latex samples were characterized using; FTIR, dynamic light scattering (DLS) and field emission-SEM (FESEM) techniques. Mechanical properties of nanocomposite latex samples were evaluated using DMTA and Taber abrasion test method.The results showed the chemical interactions between MPS and silica nanoparticles. The treatment conditions such as; silane and water contents, reaction time and pH, have significant effect on the MPS grafting of nanoparticles as a result of increase in the rate of silane hydrolysis. FTIR and DLS studies indicated successfully performing of in situ polymerization of silica/acrylate nanocomposites. The latex particles size was affected by inclusion of either un-treated or MPS-treated nanoparticles. The average diameter of latex containing MPS-treated nanoparticles (129nm) was larger than that of neat latex (98nm). The FESEM study revealed a better distribution of the treated nanoparticles compared with their untreated counterparts. Eventually, the results revealed that addition of either un-treated or MPS treated nanoparticles significantly enhanced mechanical properties of acrylate latex samples.