The effect of processing parameters on the flexural properties of unidirectional carbon fibre-reinforced polymer (CFRP) composites

The flexural properties (e.g., strength, elastic modulus) of unidirectional carbon fibre-reinforced polymer matrix composites were optimised by controlling the following processing parameters during manufacture: (i) concentration of epoxy (45-65 wt.%) within an acetone solution for wetting the carbon fibres, (ii) compressive pressure (0.25-1.25 MPa), and (iii) holding time (20-40 min) applied during vacuum autoclave curing at 120 °C. Flexural properties of the resulting composites were evaluated using the three-point bend configuration in accordance with the ASTM D790-03 standard. Overall it was concluded that optimum flexural properties (e.g., 1292 MPa flexural strength) were achieved using a 50 wt.% epoxy solution, 1.0 MPa compressive pressure, and 30 min holding time during vacuum autoclave curing.