3.2. Mechanical properties of composites
Filler loading, filler type and particle size, had significant effects on all the measured mechanical properties of GNR composites. Superior or comparable mechanical properties to those of carbon black filled composites were achieved by partial replacement of carbon black with low loadings (5 and 10 phr) of all waste-derived fillers (Fig. 3). Remarkably, the micro sized ES particles, in combination with carbon black, showed reinforcement beyond carbon black alone. The addition of micro sized ES up to 20 phr (57% replacement of carbon black in the composite), improved tensile strength and elongation while maintaining similar values of 300% modulus and hardness to those achieved by carbon black alone. In addition, 5 phr of micro sized TP and CFA and 5 phr of macro sized GB had tensile strength of 25.79 ± 0.08 MPa, 24.05 ± 0.26 MPa and 26.28 ± 0.41 MPa respectively, significantly higher than composites manufactured with carbon black alone (21.3 ± 0.75 MPa).