A facile methodology has been developed to synthesize silver-filled multiwalled carbon nanotubes (S-MWNTs)-polyimide (PI) nanocomposites with high thermal conductivity for applications in flexible printed circuits or buried film capacitors, requiring efficient heat dissipation. MWNTs functioned as modules to facilitate the distribution of Ag particles within PI matrix. The intercalation of Ag within MWNTs was performed using capillary action upon mixing AgNO 3 solution with PI precursor and followed by calcinations to reduce the ionic silver to Ag. The existence of Ag in the PI nanocomposites was observed from transmission electron microscope images and verified with the energy-dispersive X-ray spectrometer. Homogeneous dispersion of SMWNTs in PI matrix and strong interaction between S-MWNTs and PI were also suggested by SEM cross-section images. The thermal conductivity of S-MWNT/PI nanocomposite was a function of the content of S-MWNTs in PI matrix. The PI nanocomposite containing 1.5 wt % of S-MWNTs (S-MWNT/PI-1.5) exhibited the highest thermal conductivity, 0.37 W/mK. A decrease in thermal conductivity was observed while the surface roughness of the nanocomposite was higher than 1 lm owing to the high content of S-MWNT in PI. In addition, the modified MWNTs improved flexibility of the PI matrix. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: E182-E187, 2012

The polyimide/multi-walled carbon nanotubes (PI/MWNTs) nanocomposite film has been successfully synthesized in this study. The source of MWNTs is prepared by chemical vapor deposition (CVD) method. Then the MWNTs are washed with acid for purification before being added into the polymer matrix. The acid-modified procedure aids in dispersing MWNTs in N,N-dimethylacetamide (DMAc) solvent. Based on the results of field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), the MWNTs are embedded in PI and well-dispersed within the PI matrix. The dynamic mechanical analysis (DMA) shows that the storage modulus of nanocomposite film is increased by 68% with the addition of 1 wt% MWNTs into PI. The nanocomposite films start to decompose at or above 400 degrees C and lose 5% of its weight at 545 degrees C according to thermogravimetric analysis (TGA). Meanwhile, the electrical conductivity of the nanocomposite film with 3 wt% MWNTs, is raised more than 10 orders of magnitude from 10(-15) to 10(-5) S/cm.

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