Interlaminar Fracture Toughness of CFRP Laminates Incorporating Multi-Walled Carbon Nanotubes

Abstract

Carbon fiber reinforced polymer (CFRP) laminates exhibit limited fracture toughness due to characteristic interlaminar fiber-matrix cracking and delamination. In this article, we demonstrate that the fracture toughness of CFRP laminates can be improved by the addition of multi-walled carbon nanotubes (MWCNTs). Experimental investigations and numerical modeling were performed to determine the effects of using MWCNTs in CFRP laminates. The CFRP specimens were produced using an epoxy nanocomposite matrix reinforced with carboxyl functionalized multi-walled carbon nanotubes (COOH-MWCNTs). Four MWCNTs contents of 0.0%, 0.5%, 1.0%, and 1.5% per weight of the epoxy resin/hardener mixture were examined. Double cantilever beam (DCB) tests were performed to determine the mode I interlaminar fracture toughness of the unidirectional CFRP composites. This composite material property was quantified using the critical energy release rate, GIC. The experimental results show a 25%, 20%, and 17% increase in the maximum interlaminar fracture toughness of the CFRP composites with the addition of 0.5, 1.0, and 1.5 wt% MWCNTs, respectively. Microstructural investigations using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) verify that chemical reactions took place between the COOH-MWCNTs and the epoxy resin, supporting the improvements experimentally observed in the interlaminar fracture toughness

Improving Fracture Toughness of Polymer Concrete Using MWCNTs

“…PC incorporating 1.5% MWCNTs showed the highest increase in fracture toughness. At 1.0 wt.% MWCNTs, fracture toughness increased by 24% showing similar results to that of Yu et al [3], Tang et al [7] and Borowski et al [15] observed due to incorporating MWCNTs in fibre reinforced polymer composites. PCNC-1.5 and PCNC-0.5 showed excessive CMOD to failure and a yieldlike behavior in the curve softening region.…”

Improving Impact Resistance of Polymer Concrete Using CNTs

“…12. Similar C=O peaks were reported before in using COOH functionalized MWCNTs for improving fracture toughness of carbon fiber composites (Borowski et al 2015). It is important to note that that amide peak in the COOH-MWCNTs-epoxy nanocomposite at 1660 cm -1 appears combined with the aromatic and N-H deformation peaks in neat epoxy (Tsai et al 2015).…”

A review on mode-I interlaminar fracture toughness of fibre reinforced composites

“…This is because of the non-planar interply structure of woven-fabric composites, the interaction between the delamination crack, the matrix regions and the weave structure during propagation, will result in crack growth [11]. The interlaminar performance are characterized by their weakness towards the sheer stress and tensile stress [12]. According to Zulkifli R et al [1], when the number of layers increases, the stiffness and interlaminar fracture toughness also found to be increasing.…”