Toughened FRP composites reinforced with glass and carbon fiber

Glass fiber reinforced plastic (GFRP) and carbon fiber reinforced plastic (CFRP) composites were made using epoxy/hyperbranched polymer (HBP) blends as matrices. The morphology of the blends was investigated both in the castings and composite form. Unlike the castings, where no reduction in epoxy Tg was observed up to 15 wt% of HBP, the Tg of the blend matrix was found to decrease as a result of addition of HBP (0–20 wt%) in case of GFRP and CFRP composites. Incorporation of HBP resulted in a significant increase in impact strength in GFRP composites whereas no significant improvement was observed in case of CFRP composites. Fracture surfaces of the composites were analyzed by scanning electron microscope (SEM), which indicates a two-phase microstructure. The microstructure was found to be different in castings and composites.