A feasible route to balance the mechanical properties of epoxy thermosets by reinforcing a PCL-PPC-PCL toughened system with reduced graphene oxide

The introduction of block copolymer with low Tg blocks and epoxy host miscible blocks is one of most effective approaches to toughen epoxy thermosets. Nevertheless, this enhancement in toughness is always accompanied by decrease in tensile strength of the resulting materials, which is also extremely important in practical applications. In this work, we demonstrated a new strategy to overcome this challenge by adding the chemically reduced graphene oxide (C-RGO)1 to a triblock copolymer toughen epoxy system. For epoxy thermoset toughened by 30 wt% PCL-PPC-PCL,2 the fracture toughness was 1099 J/m3 and tensile strength was 31.5 MPa, while that of pristine epoxy thermoset is 688 J/m3 and 80.6 MPa respectively. By introducing 0.25 wt% of C-RGO, the resulting nanocomposite not only maintained high fracture toughness (c.a. 1102 J/m3), but also exhibited significantly increased strength of 51.9 MPa. Moreover, the temperature of 5% thermal weight loss was increased by more than 10 °C compared to the toughened system without C-RGO. Our work provides a simple and feasible approach to prepare epoxy thermosets with balanced toughness, strength and thermal properties.