Hydrogen adsorption onto nickel modified carbon nanotubes.

The Hot Filament Chemical Vapour Deposition (HFCVD) method was employed to study hydrogen adsorption on multi-walled carbon nanotubes (MWCNTs) modified by nickel doping. Prior to the nickel doping, effective functionalisation of CNTs was achieved by treating them in HNO3/H2O2 medium. Samples were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDS), and Fourier Transform Infrared (FTIR) and Raman spectroscopy techniques. SEM analyses revealed the morphology of the samples and the presence of nickel was identified by EDS analyses. Raman analysis revealed the enhancement of defects on the CNTs after the nickel modification. The defects created along with the catalytic activity of nickel supplied more hydrogen access to the CNTs. This was inferred from highest intensity ratio of D and G band (ID/IG) for hydrogen treated samples. However, FTIR spectra did not exhibit any C-H related bands. This confirms that the adsorption of hydrogen onto CNTs is primarily by surface adsorption.

Prediction of the mechanical properties of hydroxyapatite/polymethyl methacrylate/carbon nanotubes nanocomposite.

In this work carbon nanotubes (CNTs) were used to increase the strength and toughness of the hydroxyapatite (HA) and consequently to reduce its brittleness. The combination of CNT, HA and polymethyl methacrylate (PMMA) has led to a new composite material, which has mechanical properties superior to those of conventional HA/PMMA for biomedical scaffold in tissue engineering. PMMA is a well known bone cement which is highly compatible with HA and also it can act as a functionalizing/linking material with HA. The mechanical properties of the new nanocomposite were predicted with a self-consistent computational model taking into account the structure morphology and the orientation of the CNTs. CNT reinforced HA composite is shown to be a promising coating material for high-load-bearing metal implants. The development of this new nanocomposite based on HA/PMMA and CNTs, may significantly contribute to the bond strength of the HA/PMMA metal interface and the overall mechanical properties of the HA/PMMA coating.