Improving thermal, flame retardant and mechanical properties of epoxy resin viaexpandable graphite

In this research, the effect of expandable graphite (EG) incorporated into an epoxy aliphatic amine system was investigated. The epoxy/EG systems were prepared by using 0-4 wt% of EG. The morphological structures of expandable and expanded graphite were studied by scanning electron microscopy. The influence of EG content on the thermal, flame retardant and mechanical properties of epoxy resin was investigated using thermogravimetric analysis, oxygen index test, dynamic mechanical analysis, tensile and impact tests. TGA results showed that adding EG increases the initial decomposition and residue weights of the composites. It was found that the oxygen index, glass transition temperature and young’s modulus of epoxy/ EG systems increase up to 60 %, 3% and 50% with increasing EG concentration up to 4%(wt) respectively. On the other hand, maximum value for tensile strength, storage modulus, cross- linking density, ultimate tensile strain and impact strength were obtained when the concentration of EGwas 2wt% in the composite. These characteristics increased up to 30%, 57%, 74%, 14% and 25%, respectively.