Carbon nanotubes are commonly used to create polymer-nanotube composite for various applications. To suffice the needs of the emerging interest in utilizing nanotube, a great concern in creating a stable dispersion of the nanotube in solvent emerged. There is a paramount need to enhance the adhesion between the polymer and carbon nanotube to give a homogenous and stable dispersion throughout the polymer matrix. Thus, oxidative acid treatments are often chosen to chemically functionalize carbon nanotube in order to give such dispersing ability to the nanomaterials. In this study, purified multi-walled carbon nanotubes (MWCNTs) is oxidized under the influence of three types of oxidants i) hydrogen peroxide, ii) citric acid monohydrate and iii) mixture of 3:1 sulphuric and nitric acid. All the MWCNTs suspensions ultrasonicated for 8 hours to create opening defects on the MWCNTs to allow the surface modification to occur. In this comparative study of chemically surface modification using oxidative acid treatments, FTIR was used to examine the formation of -OH, -COOH and -C=O groups on the surface of the MWCNTs, TGA and XRD used to determine the thermal behaviour and the crystal structure studies of the modified MWCNTs respectively.

Cu nanoparticles on Al2O3 catalyst were prepared via impregnation method and two different activation conditions were examined. The morphology of the catalyst has been characterized by using scanning electron microscopy (SEM); while, the crystallography was determined by using powder X-ray diffraction (XRD). The thermal stability of the catalyst was analysed by using thermogravimetry and differential thermal analysis (TG-DTA). Overall, from the XRD pattern, it was revealed that the nanoparticles Cu catalyst produced in air and nitrogen conditions is CuO and Cu active phase. At 400°C under air condition, the crystal size of CuO produced are in between 23.57 and 23.61 nm, while in nitrogen condition the crystal size was 30.24 to 30.31 nm. These results indicate that the size of the Cu nanoparticles catalyst produced under nitrogen flow was slightly bigger compared to air conditions. The results were further confirmed using SEM image in which catalyst activation under nitrogen flow has produced abundance microcrystal structure than under air condition. Meanwhile, the thermal stability of the nano-Cu catalyst shows that the both activation procedure was a single stage of thermal degradation at 260°C.