Nanotube/Polymer Composites: Materials Selection and Process Design

摘要

The objectives of this project were (1) establish proof of principle by demonstrating enhanced polymer properties by the addition of single walled nanotubes (SWNTs), (2) provide guidelines for materials selection that give improved mechanical, electrical and/or thermal properties, and (3) define processing methods most appropriate for the materials identified. Our study of SWNT-polymer composites focuses on thermoplastics, because these materials can be readily drawn into fibers. As we have shown previously, the extensional flow exerted on the composite during fiber spinning aligns the SWNT to an unprecedented level. The anisotropic orientation of SWNT in these composite fibers provides an advantage when bolting for changes in macroscopic properties, particularly tensile strength. Composite processing and composite characterization received comparable effort in this project. Processing efforts include our coagulation method as well as in situ polymerization of nylon in the presence of well-dispersed SWNT. In addition to mechanical testing of the SWNT- thermoplastic fibers, we established methods for testing the electrical and thermal conductivity of these highly anisotropic materials. We used scattering methods for quantifying the extent of dispersion within the composites, a widely appreciated and long standing question in nanocomposites.