Structural and Physical Properties of MWNT/Polyolefine Composites

Composite materials containing multi-walled carbon nanotubes (MWNT) in polyolefine (polyethylene and polypropylene) matrix were prepared by coagulation precipitation. The morphology and structure of produced composites was investigated by scanning and transmission electron microscopy. Thermal analysis (oxidation in air) was performed for composites in temperature range 20-500 degrees C. It was shown that the addition of MWNT increases the thermal stability of composites. Electrophysical properties of MWNT/PSt composites were investigated using a four-probe technique. Observed electrical percolation threshold of composite materials is near to 3-3.5wt%. Electromagnetic (EM) response of prepared materials was investigated in broad-band region (26-37 GHz and 250-500 GHz). It was found that the EM response of MWNT/polyolefine depends on their electrophysical properties with percolation threshold near 2-3wt%.