Development of multi-walled carbon nanotubes obtained from recycled plastics by single stage pyrolysis process

The development of nanofillers from plastic waste plays a significant role as an alternative plastic waste managing method. Multi-walled carbon nanotubes were produced by a single stage chemical vapor decomposition using polypropylene as carbon source in the presence of bimetallic catalyst. A mixture of Ar/H₂ gas was used as a reducing agent for catalyst and at a later stage N₂ was used to supply inert conditions for the pyrolysis product_. Fe-Mn/Al₂O₃ catalyst was reduced at a temperature of 700 °C and PP waste was introduced at the same temperature to decompose at the surface of the catalyst to form the nanofillers. Tramission Electron Microscopy (TEM) and Raman characterization techniques were used to determine the properties of the nanofillers. The results showed that the developed nanofillers have a maximum diameter of 19.09 nm. TEM micrographs displayed lattice fringes at the magnitude of 20 nm indicating that the morphology of these nanofillers is crystalline. The Raman spectra showed the defect mode, D at the frequency of 1346 cm^-1 and the tangential mode, G is at the frequency of 1588 cm^-1. The intensity ratio I_D/I_G is 0,84 and signifies the quality of the nanofillers, as the ratio is the direct measure of the sample purity.The diameter obtained from the TEM analysis and the absence of the Radial Breathing Mode (RBM) on Raman spectra concluded that the nanofillers produced can be classified as Multi-Walled Carbon Nanotubes (MWCNT).