Preparation, structure and properties of carbon nanotube reinforced polymer nanocomposites

• After acid-treatment more carboxylic groups will be created on MWCNTs’ surfaces.
• The acid-treated MWCNTs added in polyetherimide to form the nanocomposites.
• The dielectric constant of nanocomposite at 2.5 wt% a-MWCNTs content is 9.1.
• The dielectric constants of nanocomposites higher than the ceramic/PEI composites.
• Two mixing rule were predicting the dielectric constants of nanocomposites.

Polyetherimide (PEI) nanocomposites that contain a well-dispersed filler, multi-wall carbon nanotubes (MWCNTs), were prepared. Organic acids were covalently bonded onto the π-conjugated skeleton of surface-modified MWCNTs by treating them with carboxylic acids. Analyses of X-ray photoemission spectroscopy, Raman spectra, and Fourier transform infrared spectra of MWCNTs demonstrated that the acid-treated process increased the number defects in the graphitic layers. The acid-treated process on MWCNTs (a-MWCNTs) could improve adhesions between the organic polymer and carbon nanotubes (CNTs). The dielectric characteristics of a-MWCNTs/PEI nanocomposites with various a-MWCNTs contents were measured from 10 kHz to 1 MHz using the plate method. Two mixing rule models, the Lichtenecker logarithmic model and Yamada model, were applied to predict the dielectric constants of a-MWCNTs/PEI nanocomposites. The results indicate that the Yamada model was more effective than the Lichtenecker logarithmic model at predicting the dielectric constants of the a-MWCNTs/PEI nanocomposites.