Thermo-mechanical characterization of epoxy/clay nanocomposites as matrices for carbon/nanoclay/epoxy laminates

Microstructural and thermo-mechanical characterization were performed on epoxy–clay nanocomposites, to be used as matrix for continuous carbon fiber reinforced composites, containing various amounts of clays having different hydrophilicity. XRD tests displayed that the dispersion degree of the clay lamellae was strictly correlated to their hydrophilicity, while DSC tests revealed that the crosslinking degree was negatively affected by the presence of most hydrophilic clays. Therefore, the balance between polymer–filler interaction and crosslinking degree influenced the final properties of the resulting composites. The mechanical behaviour, both under quasi-static and impact conditions, was positively affected by resin nanomodification. Fracture toughness and threshold to crack initiation under cyclic loading were also interestingly improved. the effect of nanoclay introduction on the quasi-static tensile properties of the carbon/epoxy laminates was negligible, Charpy impact tests on nanomodified epoxy/carbon fiber cross-ply laminates evidenced slight enhancements of the elastic modulus and of the energy adsorption capacity with respect to the unfilled epoxy–carbon composites. Moreover, drop weight test on laminates evidenced improvements in energy absorption capacity due to resin nanomodification.