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In order to realise the potential of graphene nanocomposites it is vital to control the degree of dispersion and achieve a strong graphene/polymer interface. Herein, we developed a facile ‘grafting to’ functionalization approach for graphene nanoplatelets. NH 2 -terminated graphene nanoplatelets (NH 2 -GNPs) prepared by diazonium coupling were used as a ‘platform’ to covalently graft PMMA chains to...
In order to clarify the effect of nanostructure upon the tensile strength of polyacrylonitrile (PAN)-based carbon fibres, experimental as well as theoretical studies have been performed. A new technique for the quantitative evaluation of the high strength region has been developed by combining the loop test with Raman spectroscopic measurements to overcome uncertainties in fibre stress, which have...
Graphene was grown on copper and repeatedly transferred onto a GaAs semi-insulating substrate to form multilayers (1–10). These manually stacked graphene layers resulted in appreciable local variations of optical properties due to the local differences of stacking orders. In addition, most of the observed 2D/G intensity and area ratios of an n-multilayer CVD graphene is consistent with the characteristics...
In the decade since the first isolation and identification of graphene, the scientific community is still finding ways to utilize its unique properties. The present review deals with the preparation and physicochemical characterization of graphene-based elastomeric nanocomposites. The processing and characterization of graphene and graphene oxide are described in detail, since the presence of such...
Polarized Raman spectroscopy has been employed to characterize transverse sections of graphene monolayers upon both a copper substrate and a polyester film. Well-defined Raman spectra can be obtained from the one atom thick transverse sections of graphene because of the strong resonance Raman scattering. The intensity of Raman 2D band (I 2D ) is independent of the axis of laser polarization...
We have used UV-Raman spectroscopy to study the sp3 structure in polyacrylonitrile- and pitch-based carbon fibres with Young’s modulus values in the range of 90–830GPa. The composite microstructure of these carbon fibres comprises an amorphous carbon phase that transfers the load to a reinforcing graphite crystalline phase. The intensity ratio of the T, D and G Raman bands showed that the low modulus...
Cellulose nanofibres have been fabricated by electrospinning of a cellulose acetate solution followed by deacetylation. The cellulose nanofibres were then carbonized using temperatures in the range 800–2200°C and the resulting carbon nanofibres (CNFs) were characterized using transmission electron microscopy, X-ray diffraction and Raman spectroscopy. A graphitic structure was observed for CNFs treated...
We have used the Mori–Tanaka theory to develop a new micromechanical model to predict the Young’s modulus for carbon fibres, taking into account both the crystallites and amorphous components of the fibre structure. In order to follow the dependence of the mechanical properties of the fibres upon nanostructure, we prepared five different types of PAN-based fibres, with Young’s moduli in the range...
High-modulus carbon fibres from different precursors were submitted to an oxygen plasma-treatment under similar conditions. Single-fibre epoxy composites were prepared from them, and fragmentation tests were performed in order to characterise fibre-matrix interfacial adhesion. Raman spectroscopy has been used in the present work to map the strain along the fibre during tensile loading of the matrix...
The effect of an oxygen plasma treatment upon the structural and morphological properties of high-modulus carbon fibres has been studied by means of several characterisation techniques. Scanning electron microscopy showed that there were only minor changes of the morphology of the fibres following treatment. X-ray diffraction traces revealed that there were differences in structural parameters between...
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