Evaluation of ordered mesoporous silica SBA-15 dispersed in epoxy resin

Abstract

To obtain the mesoporous nanostructured SBA-15 silica particles, a chemical reaction was perfomed using a template – a triblock copolymer (Pluronic 123®) - and a silica source - the tetraethyl orthosilicate - in acid medium. These silica particles were obtained by classical chemical reaction method and irradiation process (gamma rays from 60Co-Gammacell) at absorbed dose values of 0.5 kGy, 10 kGy and 25 kGy. Then, these silica particles were dispersed in epoxy resin Araldite® GY260 (diglycidyl ether of bisphenol A - DGEBA) and a cure agent. The particles dispersion was evaluated by two methodologies: a) Melt blending mode, where silica particles are dispersed in hot resin; b) Solvent-blended solution mode, where silica particles are dispersed in epoxy resin/acetone mixture in order to prevent the agglomeration of the inorganic phase. The silica particles had the specific surface area calculated from BET (Brunauer-Emmett-Teller) equation, while the BJH (Barrett- Joyner-Halenda) equation was used to determine pore volume and average diameter. Silica particles presented high surface area and pores arranged in hexagonal nanoscale diameter. The TEM images for irradiated silica particles have confirmed the hexagonal pore ordering in SBA-15 even using low gamma absorbed doses. The infrared absorption spectra (FTIR) confirmed that the added organic solvent has been effectively removed. Images of optical microscope revealed dispersion of the components by solvent-blended solution mode allows a better components interaction.