Effect of Graphene Content on the Mechanical Properties of PMMA Composites

The effect of graphene reinforcement on tensile strength, elastic modulus and fracture toughness of the graphene-PMMA composites was investigated. Graphene-PMMA composites were prepared with 0.5, 1, and 3 wt% graphene incorporated. It was found that the graphene flakes were self-oriented to the horizontal direction. The untreated graphene was found has little effect on the tensile strength of the composites, but the fracture toughness was improved by 40–50% with 0.5–1% graphene incorporated. Examination of the fracture surfaces of the samples after tearing tests found that the graphene made the cracks deflection and branching happen during crack propagation, which increased the energy consumed for fracture of the composites. Tensile tests with single edge notched samples were also performed, the observation at the notch tip found the plastic deformation zone formation around the notch tip on the samples with graphene incorporated, while the pure PMMA samples all had brittle fracture.