Mechanical and morphological properties of carbon nanotubes polymeric composites

Abstract

Carbon nanotubes (CNT) are incorporated to the polymers to enhance their electrical and mechanical properties. All of the samples in this thesis were prepared from the liquid phase using the solution casting method. The change in morphological and mechanical properties of PVA based composites with the addition of double walled carbon nanotubes has been studied using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), differential thermal gravimetric analysis (DTGA), dynamic thermal analysis (DMTA), and tensile testing. Three different solvents i.e. water, dimethylsulfoxide (DMSO), and N-methylpyrrolidone (NMP) have been used for solution based composite formation. It has been found that the composite properties are affected not only by the solvent boiling point but also by the polymer solubility and, more importantly, the affinity of the carbon nano tubes CNTs for the solvent. The data obtained for the NMP solutions is consistent with solvent trapping at the polymer-nanotube interface, whereas the DMSO study has shown that the solvent remains trapped more in the matrix than at the CNT-PVA interface. Almost no water was found in water based samples. Maximum reinforcement was found with the composites prepared using water as the solvent, those prepared with DMSO exhibited intermediate reinforcement, while NMP composites showed a reduction in mechanical properties compared with their respective polymer only samples.