Mechanical Properties of Aligned Carbon Nanotube/Epoxy Composites

Abstract

This study examined the mechanical properties of aligned multi-walled carbon nanotube (CNT)/epoxy composites processed using a hot-melt prepreg method. Vertically aligned ultra-long CNT arrays (forest) were synthesized using chemical vapor deposition with high growth rate, and were converted to horizontally aligned CNT sheets by pulling them out. An aligned CNT/epoxy prepreg was fabricated using hot-melting with B-stage cured epoxy resin film. High quality composite film specimens were produced. Tensile tests were conducted to evaluate the mechanical properties. The resultant composites exhibit high Young's modulus and tensile strength. For example, the maximum elastic modulus and ultimate tensile strength of a CNT (32.8 vol.%)/epoxy composite were 89 GPa and 239 MPa. These values were, respectively, 36 and 5 times higher than those of the epoxy resin. CNT orientation angle distribution was quantitatively examined. Mori-Tanaka theory was adopted to estimate the elastic moduli of the composites. The estimated Young's modulus of CNT was 680 GPa. The numerical calculation results suggested that the Young's moduli of unidirectional CNT composites (32 vol.%) and 2-D randomly oriented CNT composites (35 vol.%) are almost equal to those of unidirectional and quasi-isotropic CFRP laminates.