Investigation of Hybrid Effects of CNT and Nanoclay in Tailoring Mechanical and Electrical Properties of Epoxy
عبدالمجيد حمودة, علي اسماعيلي
كلية الهندسة-جامعة قطر · قطر
Many studies performed on multifunctional properties of epoxy-basednanocomposites reinforced with CNTs and nanoclay whereas synergetic effects ofCNTs and nanoclay on mechanical and piezoresistive behavior of ternary statenanocomposites still remains unaddressed. Therefore, the hybrid effects of CNTs andMontmorillonite platelets on the mechanical, electrical and piezoresistive performancesof the epoxy are addressed in this study. The project was divided into two main phases.In the first phase, different CNTs morphologies (SWCNTs and DWCNTs) and weightconcentrations were used. For the second phase, CNT content was kept constant whiletwo different nanoclay loadings were used for the ternary states. In fact, thenanocomposites were prepared in two different states, i.e. the binary state, including0.1wt.% CNTs, and the ternary states, including 0.1wt.% CNT and two levels of NC(0.5wt.% and 1wt.%). SEM, FESEM, and XRD were used for the microstructuralanalysis of the materials while tensile and mode I fracture tests were performed formechanical and piezoresistive characterizations. In overall, by taking into considerationof multifunctional properties including tensile strength, fracture toughness, electricalconductivity and sensitivity, it was stated out that the ternary nanocomposites developed in phase 2 demonstrated better performance compared to the ones producedin phase 1. In fact, low tensile strength along with high variations observed in phase1,raised questions for the effective exploitation of CNTs in multifunctional propertiesenhancement. On the other hand, highly monotonous outcomes especially for tensilestrength without sacrificing other properties indicated the effective exploitation ofnanofillers in tailoring material performances in phase 2. The addition of nanoclay toCNTs doped epoxy resulted in better CNTs dispersion, hindering CNTs reagglomeration. Significant increase in critical stress intensity factor and critical strainenergy release rate compared to the neat epoxy was obtained for the hybridnanocomposites developed in phase 2 due to crack bridging and crack deflectionmechanisms. The electrical conductivity of the ternary state materials increasedsubstantially with respect to the binary nanocomposite. The hybrid nanocompositesalso manifested higher piezoresistive sensitivity and a more robust signal in tensile andfracture tests, respectively.