Surface nanogrooving of carbon microtubes

Extrusion processing of carbon tubes can be problematic due to their poor interfacial interactions with polymeric matrices. Surface chemical modification of carbon tubes can be utilized to create bonding sites to form networks with polymer chains. However, chemical reactions resulting in intermolecular primary bonding limit processability of extrudate, since they cause unstable rheological behaviour, and thus decrease the stock holding time, which is determinative in extrusion. This study presents a method for the synthesis of carbon microtubes with physically modified surface area to improve the filler and matrix interfacial interactions. The key concept is the formation of a nanogrooved topography, through acoustic cavitation on the surface of processing fibres. The effect of nanogrooving on roughness parameters is described, along with the role of surface modified carbon tubes on rheological behaviour, homogeneity, and coherency of extrudate. The measurements showed that nanogrooving increases the surface area of carbon microtubes, as a result, die swelling of the extrudate is reduced. Furthermore, after solidification, the mechanical strength of composite is reinforced due to stronger interactions between nanogrooved carbon tubes and polymer matrix

Graphene radicals: manipulation and applications

This project reveals how progressive oxidation and reduction, which alters the physical and chemical structures modulates the free radical and reactivity of GO. The ability of graphene nanosheets rich in radicals were examined as both initiator and cross linker to fabricate polymer composites

Effect of natural fibre reinforcement on the sound and vibration damping properties of bio-composites compression moulded by nonwoven mats

Biodegradable natural fibre composites are increasingly developed for lightweight structural applications in automobile and construction industries with significant environmental benefit. This work aims to explore the sound and vibration properties of natural fibre composites that inevitably suffer menace of vibrations during their operations as engineering structures. Natural fibres (bamboo, cotton, flax) and polylactic acid (PLA) fibres were blended, carded, laid up and finally needle-punched to nonwoven mats before being consolidated at elevated temperature under compression. Vibration damping and acoustic measurements were conducted on these natural fibre composites and their behaviour was compared to that of a commercial panel, made of polypropylene (PP) matrix reinforced with hemp and kenaf fibres. From both the coincidence frequency analysis and wave number amplitude analysis, the cotton/bamboo/PLA composite laminate showed the best acoustic performance (coincidence frequency of 2448 Hz) that is related to the fineness of cotton fibres, bending stiffness, natural frequency and density of the composite panel. The results suggest that the bamboo/cotton hybrid composites can be a viable candidate for engineering applications that require good bending properties, high sound absorption and vibration damping properties