Highly conducting poly(methyl methacrylate)/carbon nanotubes composites: Investigation on their thermal, dynamic-mechanical, electrical and dielectric properties

International audienceNanocomposites of poly(methyl methacrylate) (PMMA) containing various multi-walled carbon nanotubes (MWCNT) contents were prepared using melt mixing. Several techniques were employed to study the influence of the MWCNT addition on the thermal, mechanical, electrical and dielectric properties of the PMMA matrix. The electrical percolation threshold () was found to be 0.5 vol.% by performing AC and DC conductivity measurements. Significantly high conductivity levels () were achieved: exceeds 10 S/cm already at 1.1 vol.%, the criterion for EMI shielding ( > 10 S/cm) is fulfilled at 2.9 vol.%, and the highest loaded sample (5.2 vol.%) gave a maximum value of 0.5 S/cm. Dielectric relaxation spectroscopy measurements in broad frequency (10−10 Hz) and temperature ranges (-150 to 170 °C) indicated weak polymer-filler interactions, in consistency with differential scanning calorimetry and dynamic mechanical analysis findings. Weak polymer-filler interactions and absence of crystallinity facilitate the achievement of high conductivity levels in the nanocomposites

Influence of surface treatment of multiwall carbon nanotubes on the properties of polypropylene/carbon nanotubes nanocomposites

Nanocomposites based on polypropylene (PP) and surface modified multiwall carbon nanotubes (CNT) were prepared by melt mixing. For comparison, unmodified CNT were also used as fillers. The surface modification of CNT was done by treatment with a combination of anionic and cationic surfactants at different molar ratios using week and strong sonication power output during modification. The modification of nanotubes was done to improve the filler dispersibility in the PP matrix. However, the modification of the filler resulted only in small morphological differences of prepared composites, but the electrical conductivity of the samples depends on filler type and content. Mechanical and thermal properties of the nanocomposites were studied and the results are discussed in relation with the preparation parameters during the modification of CNT. © 2010 John Wiley & Sons, Ltd

Dielectric and thermomechanical properties of polypropylene/multi-walled carbon nanotubes nanocomposites

The purpose of this work is to examine the dielectric, electrical and thermo-mechanical properties of multi-walled carbon nanotubes (MWCNT) filled polypropylene nanocomposites formed by melt-mixing. To that aim dielectric relaxation spectroscopy (DRS) and dymamic mechanical analysis (DMTA) were employed. The results are discussed in terms of nucleating action of MWCNT and interfacial polymer-filler interactions. Special attention is paid to percolation aspects by both ac conductivity measurements for the samples which are above the percolation threshold and permittivity measurements for the samples which are below percolation threshold. © 2008 Materials Research Society