| 초록 |
Carbon nanotubes (CNTs) are one of the preferred fillers for polymer composites due to their exceptional electrical and mechanical properties. We have studied degradation of poly (methyl methacrylate)-CNT nanocomposite thin films, using a UV-ozone and an e-beam radiation as a function of CNT concentration. We have shown that the addition of CNT fillers can have a dramatic reinforcement effect on the nature of degradation by both high-energy radiations and thermal treatments, where polymer free radicals are mainly responsible for the proliferation of degradation. In addition, CNT networks can effectively disperse the radiation energy. The saturation in the reinforcement effect was observed when a concentration of CNT was approximately 0.5 wt %. This concentration was interpreted in terms of a critical concentration for percolation of the CNT network, and the result was consistent with the sheet resistivity measurement for which physical contacts between CNT fibers were evident. The results are then correlated with systemic study of the rheological and chemical properties of polymer-CNT composites by thermal analysis (TGA and DSC). Finally, the feasible shielding mechanisms and roles of the CNT molecules in polymer matrices will be discussed in detail. This research was supported by a grant(M105KO010001-05K1501-00110) from 'Center for Nanostructured Materials Technology' under '21st Century Frontier R&D Programs' of the Ministry of Science and Technology, Korea |
