Graphene dispersed by pyrene-terminated polyethylene glycol for reinforced epoxy composites

摘要

Incorporating graphene into epoxy composites is a facile strategy to improve their mechanical performances. However, the uniform and reliable dispersion of graphene within epoxy matrix remains a large challenge owing to the intrinsic difference in chemical properties. Here, pyrene-functionalized polyethylene glycol (Py-PEG-Py) was easily synthesized and utilized as a dispersant to homogenize graphene. The effect of graphene loading on mechanical performances of reinforced epoxy composites was also investigated. As 0.01 to 0.05 wt of graphene were incorporated in epoxy resin, the resulted composites exhibited excellent improvement in flexural strength and fracture toughness compared with neat epoxy. Typically, the flexural strength increased from 63.57 +/- 1.5 MPa for neat epoxy to 108.36 +/- 1.9 MPa (about 70.5) for composite, and the fracture toughness (K-IC) increased from 1.25 MPa m(1/2) for neat epoxy to 2.15 MPa m(1/2) (around 72) for composite modified with only 0.04 wt of graphene and 4 wt of Py-PEG-Py. Crack pinning caused by well dispersed graphene was contributed to enhancement of the fracture toughness. This work reveals a tiny amount graphene can also largely improve the mechanical properties of composites, providing a feasible approach to disperse graphene and fabricate high performance graphene composites.