| 内容提要: |
Carbon nanotube (CNT) is an attractive material to many scientists worldwide due to its outstanding thermal and mechanical properties. In this paper, magnetic carbon nanotube (mCNT) with excellent magnetic response was successfully synthesized by coating iron oxide particles. In order to improve the thermal conductivity and mechanical strength of polyvinylidene fluoride (PVDF) composite, mCNT was supplemented and aligned under the external magnetic field during the composite fabrication. Subsequently, orientation effects of mCNT, including the in-plane, through-plane and random patterns, on the overall thermal performance of mCNT-PVDF composite were evaluated by the X-ray diffraction, scanning electron microscope, transmission electron microscope and thermal conductivity meter, and further simulated by Effective Medium Approximation model. The results indicate that the thermal conductivity of mCNT-PVDF composites is related to the anisotropy and the thermal resistance of mCNT, and could be improved by controlling the orientation of the mCNT. The thermal conductivity of vertically-aligned mCNT-PVDF composite is 62% higher than that of unaligned one. In addition, the aligned mCNT-PVDF composite exhibits excellent mechanical strength and heat exchange ability, which makes it a potential material for use in the heat exchange industry. (C) 2017 Elsevier Ltd. All rights reserved. |