| The discovery of carbon nanotubes (CNTs) by Iijima in 1991 had brought a widespread research because of their outstanding, fabrication techniques and novel applications. The application of polymer/carbon nanotubes composites has extensively been paid attention. However, many superior performance of carbon nanotube is also not fully reflected, and a key issue is to disperse the nanotubes in a polymer matrix. In this thesis, nanocomposite films were prepared, in which polyvinyl alcohol (PVA) was used as the matrix and multi-walled carbon nanotubes were used as the filling component.Multi-walled carbon nanotubes were modified by the use of strong acid oxidation in order to improve the dispersion. FTIR, UV-Vis and TEM methods were employed to measure the properties and dispersion of carbon nanotubes. As a result, carboxyl groups were successfully introduced onto the surface of multi-walled carbon nanotubes by the acid oxidation method. Sodium dodecyl benzene sulfonate (SDBS) of the 0.04wt% concentration was useful for the dispersion of nanotubes.A facial layer-by-layer method, combined with glutaraldehyde cross-linking, was used to prepare MWNT/PVA multilayer films. SEM, UV-Vis, FTIR were used to characterized the films. The results showed that 300 layers film exhibited very uniform dispersion of carbon nanotubes. Glutaraldehyde cross-linked reaction of composite membrane enhanced the mechanical properties and thermal stability.Buckypapers were produced by a facial filter method. The cross-link reaction of glutaraldehyde with the carboxyl groups on the surface of the nanotubes resulted in an enhanced mechanical property of the papers. Buckypaper/PVA composite membranes were prepared and characterized by means of SEM, TGA, DSC, DMA and tensile testing. The results showed that, carbon nanotubes formed uniform network structure in the composite films of Buckypaper/PVA. The cross-linked composite membranes exhibited the high thermal stability and the enhanced mechanical property.
|
PDF Full Text Request