Thermal and toughness property studies on a polybenzimidazole-modified epoxy resin system

The effect of polybenzimidazole (PBI) on a silica-filled epoxy resin matrix has been investigated. Polybenzimidazole (PEI) was incorporated into a dif unctional epoxy resin matrix to the extent of 10%, before being cured with an anhydride hardener. The effects of PBI on the curing reaction and glass transition temperature (T-g) and on the toughness of the cured epoxy matrix have been studied using differential scanning calorimetry (DSC), thermogra vimetric analysis (TGA) and a universal testing machine (Instron). The resu lts indicate that the PBI modifier enhanced not only the glass transition t emperature of the difunctional epoxy matrix but also its toughness, by its catalytic action. Further investigations have been carried out on the fract ured specimens, using scanning electron microscopy (SEM) to support the enh anced toughness property of the epoxy matrix. (C) 2000 Society of Chemical Industry.