We report in this paper on the preparation of nitrogen-doped multi-walled carbon nanotube (N-MWNT)/high-density polyethylene (HDPE) composites using melt blending. The presence of N-MWNTs in HDPE and morphology of the composites were investigated using scanning electron microscopy (SEM) and Raman spectroscopy techniques. The crystallization of the nanocomposites is subsequently discussed using GS-1101 mw X-ray diffraction combined with Raman analysis. Methods Materials The main materials used in

this study are N-MWNTs (> 97% purity) with an outer mean diameter around 40 nm and a length over 10 μm. These nanotubes were synthesized by catalytic chemical vapor deposition (CCVD) technique using a mixture of C2H6/Ar/NH3 and 20 wt.%

iron catalyst supported by alumina powder. The polymer matrix RG7112 molecular weight used is HDPE with trade name TR144, supplied by Sonatrach Company CP2K (Skikda, Algeria). The melt index of HDPE pellets is 0.30 with a density of 0.942 to 0.947 g/cm3. Nanocomposite preparation N-MWNTs/HDPE were Y-27632 supplier prepared via the melt-compounding method using a twin-screw mixer (Brabender, Duisburg, Germany), the processing temperature was kept at 167°C, and the screw speed amounted to 100 rpm for 10 min. The weight fractions of N-MWNT filler were fixed at 0.1, 0.4, 0.8, and 1.0 wt.%. The composite was then hot-pressed at 177°C, under a pressure of 100 bars for 5 min, in order to obtain films using Aspartate 50 × 70 × 0.5 mm3 mold dimensions. In addition, a reference sample of bare HDPE was prepared in a very similar way. Characterization techniques The morphology of the N-MWNTs was examined by SEM on a JEOL 6700-FEG microscope (Akishima, Tokyo, Japan). High-magnification transmission electron microscopy (HRTEM) observations were carried out using a JEOL JEM-2010 F under an accelerated voltage of 200 kV with a point-to-point resolution of 0.23 nm. The thermogravimetric analysis (TGA) was performed on a Q5000 apparatus (TA Instruments, New Castle, DE, USA) where the combustion ran in air atmosphere at a

flow rate of 20 ml/min, up to 1,000°C at 10°C/min. Raman spectroscopy was carried out on a micro-Raman Renishaw spectrometer Ramascope 2000 (Gloucestershire, UK), with a spot size of 1 μm2, a resolution of 1 cm-1, and a He-Ne laser beam operating at an excitation wavelength of 632.8 nm. X-ray diffraction measurements have been performed by PANalytical system (Almelo, The Netherlands; CuKα as a radiation source with λ = 1.0425 Ǻ, 2θ from 10° to 60°). Results and discussions Analysis of carbon nanotubes SEM studies give further information on the morphology and microstructure of the prepared N-MWNTs. Figure 1 is a typical magnification HRTEM image of the synthesized product showing the bamboo-shaped MWNTs with 97% purity and high selectivity (approximately 12 to 100 nm) with an outer diameter around 40 nm [19, 20]. Figure 1 HR-TEM (a) and SEM (b) micrographs of N-MWNTs.