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Polymer/carbon nanotube (CNT) nanocomposites have received much attention recently. In this study, we attempt to enhance the electrical conductivity of polyimide (PI) by variously modifying multiwall carbon nanotube (MWNT). We report the successful synthesis of PI/MWNT composite films using a blending process, and examine their properties and morphology. We modified MWNT by three different methods: thermal purification (U-CNT), oxidation with HNO 3 (N-CNT) and modification with a silane coupling agent (G-CNT). We confirmed the successful preparation of the modified MWNTs by Fourier transform infrared (FTIR) and Raman spectroscopy, and transmission electron microscopy (TEM). The low amorphous surface characteristics of N-CNT produced low surface resistance in the range of 10 5 -10 6 X/cm 2 for the PI/ N-CNT composites, which dispersed the buildup of electrostatic charge and improved dispersion. On the other hand, the better miscibility and interaction between G-CNT and PI, for the PI/G-CNT composites present superior thermal stability and mechanical properties.

In this research, multiwalled carbon nanotube (MWNT) was oxidized and then modified to form carboxylic groups (ACOOH) on the surface and the end of the tube. After that, the MWNT was added to polyimide matrix to enhance its mechanical and electrical properties by in situ polymerization and blending. The PI/ MWNT composites were obtained by spin coating and multistep thermal curing process. The comparison of in situ polymerization and blending as well as the effect of unmodified and modified MWNT were discussed in this study. The results indicate that in situ polymerization is able to make a perfect dispersion by adding modified MWNT into polyimide matrix. Thermal and mechanical properties of the composites can be improved by hydrogen bonding interaction between the modified MWNT and polyimide matrix. Electrical resistance of the composites can be decreased to meet the criterion of electrostatic charge (ESC) mitigation as the surface resistance is reduced into the range of 10 6 -10 10 X/cm 2 by adding modified MWNT.