Processing a glass fiber reinforced vinyl ester composite with nanotube enhancement of interlaminar shear strength

Carbon nanotubes have been considered as a promising means of enhancing the properties of advanced composites in a range of polymer systems. Expected property enhancements include high strength and stiffness, improved toughness, impact and through-thickness properties. Z-axis properties like shear strength are of special interest for laminated composite structures subjected to transverse loads. This paper reports the processing of a glass fiber reinforced vinyl ester composite with nanotube integration and examines the reinforcement potential on interlaminar shear strength. Several sidewall functionalized nanotube derivatives were also prepared in order to obtain high dispersion and matrix bonding. Carbon nanotube enhanced vinyl ester/glass fiber composites were fabricated by a vacuum assisted resin transfer molding process. Overcoating the glass fiber weave with nanotubes and processing modification led to enhancement of the interface properties. A maximum of 45% increase in shear strength over control sample was observed on several types of nanotubes with a very small amount of nanotubes (0.015 wt%) coated in the midplane ply.