• Composites Research
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• v.28 no.4
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• pp.232-238
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• 2015

As a new method to predict the degree of dispersion in carbon nanocomposites, the electrical resistance (ER) method has been evaluated. After CNT epoxy resin was dropped on CF tow, the change in electrical resistance of carbon fiber tow was measured to evaluate dispersion condition in CNT epoxy resin. Good dispersion of CNTs in carbon nanocomposite exhibited low change in ER due to wetted resin penetrated on CF tow. However, because CNT network was formed among CFs, non-uniform dispersion occurred due to nanoparticle filtering effect by CF tow. The change in ER for poor dispersion exhibited large ER signal change. The change in ER was used for the dispersion evaluation of CNT epoxy resin. Correlation between interlaminar shear strength (ILSS) and dispersion condition by ER method was established. Good CNT dispersion in nanocomposites led to good interfacial properties of fiberreinforced nanocomposites.

• Composites Research
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• v.22 no.5
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• pp.8-14
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• 2009

Interfacial evaluation of glass fiber reinforced carbon nanotube (CNT)-epoxy nanocomposite was investigated by micromechanical technique in combination with wettability test. The contact resistance of the CNT-epoxy nanocomposite was measured using a gradient specimen, containing electrical contacts with gradually-increasing spacing. The contact resistance of CNT-epoxy nanocomposites was evaluated by using the two-point method rather than the four-point method. Due to the presence of hydrophobic domains on the heterogeneous surface, the static contact angle of CNT-epoxy nanocomposite was about $120^{\circ}$, which was rather lower than that for super-hydrophobicity. For surface treated-glass fibers, the tensile strength decreased dramatically, whereas the tensile modulus exhibited little change despite the presence of flaws on the etched fiber surface. The interfacial shear strength (IFSS) between the etched glass fiber and the CNT-epoxy nanocomposites increased due to the enhanced surface energy and roughness. As the thermodynamic work of adhesion, $W_a$ increased, both the mechanical IFSS and the apparent modulus increased, which indicated the consistency with each other.