Mechanical properties and morphology of epoxidized soyabean-oil-modified epoxy resin

Epoxidized soyabean oil (ESO) has been used to toughen epoxy resin cured with an ambient temperature hardener. The ESO was prepolymerized before blending with epoxy resin to obtain modified networks having various concentrations of ESO. The modified networks were also made by blending the ESO with epoxy resin by a one-stage process. All the modified networks were characterized for their thermal, flexural and impact properties, and compared to the parent epoxy network. The optimum properties were obtained at 20 parts per hundred grams of resin (phr) of ESO. The impact behaviour is explained in terms of morphology observed by scanning electron microscopy, (C) 2001 Society of Chemical Industry.