Improved crack resistance and fracture toughness using MWCNT modified epoxy for delaminated composite structures

We studied the mechanical and fracture properties of multi walled carbon nanotube (MWCNT) reinforced epoxy composites motivated by an extensive literature review that confirmed nanocomposites with around 3% by weight MWCNTs. As they are very efficient in arresting any potential cracks. Such nanocomposites have also been shown to prevent crack propagation by the possible mechanism of crack bridging, as well as exhibition of excellent mechanical properties. The initial phase of our experimental study which comprised specimen preparation and tensile testing of MWCNT-epoxy composites has concluded that there is excellent improvement in mechanical properties even with lower amounts of MWCNTs in the composite. We found with 0.3% by weight MWCNT in epoxy composite improves the mechanical properties by 75%, as exhibited in the modulus, ultimate tensile strength, and toughness from a tensile test on a dog-bone shaped specimen. Of interest, 0.1% MWCNT-epoxy specimen shows an overall increase by 20% in the mechanical properties. An intermediate experimental investigation of variation in sonication time intervals, curing temperatures, and curing time intervals indicated a minor deviation of around 4-5% in the mechanical properties, thus concluding that initial tensile improvements are robust against process conditions. (C)2014 Published by Elsevier Ltd.