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Abstract: Multi-walled carbon nanotubes (MWCNTs) were filled into polycarbonate (PC) by large scale extruder, and some studies were carried out on as-produced composite. The results showed PC composite containing 1wt.% of MWCNTs had a tensile strength 4.5% higher than neat PC, and the elastic modulus of PC/MWCNTs composite increased obviously with MWCNTs loadings. The electrical resistivity measurements indicated a percolation of MWCNTs near 5wt.% (3.4vol.%) for the composite. Either the decrease in the fluidity of the composite melts with the increase of carbon nanotubes (CNTs) loadings or the unexpected shortening of CNTs in extrusion was supposed to have weakened the effects of CNTs as a reinforcing agent or a conductive filler. [Copyright &y& Elsevier]

Abstract: Thin carbon nanotubes were synthesized by catalytic decomposition of CH4 over MoCoMgO catalyst. We obtained bundles of ordered nanotubes under hydrogen gas and disordered nanotubes under nitrogen gas over the same catalyst. The formation mechanism of nanotube bundles was discussed. The number of the tube walls was 2–5 with the corresponding diameters of 3–6 nm. We obtained a high production yield of 500 wt.% for the thin carbon nanotubes compared to the weight of the supplied catalyst. Moreover the duration of the hydrogen pretreatment was also found to have different effects on the yield of nanotubes under different carrier gases. [Copyright &y& Elsevier]

Abstract: Cutting carbon nanotubes is an important issue encountered in many potential applications. It was found that multi-walled carbon nanotubes(MWNTs) could be cut short efficiently by a two-roller mill. The addition of poly (methyl methacrylate) (PMMA) could increase the cutting efficiency and make the lengths of as shortened carbon nanotubes more uniform. Both the milling times and MWNTs'' content in PMMA composite had positive effects on the final lengths of as shortened MWNTs. The shortened MWNTs obtained from PMMA composites containing 25% MWNTs after being milled for 20 times showed a narrow length distribution of 250–300 nm and could form a homogeneous and stable dispersion in H2CCl2. [Copyright &y& Elsevier]

Abstract: Polycarbonate(PC) layer was introduced onto the surface of the purified carbon nanotubes(CNTs) by solution mixing. The as encapsulated nanotubes can be effectively cut short by ball milling for several hours. The average length of carbon nanotubes after 10 h of ball milling is about 60 nm. The polymer layer acts as a micro-cutting medium and stimulates shortening the carbon nanotubes. [Copyright &y& Elsevier]

Abstract: Carbon nanotubes-based TiO2 composites were fabricated by hydrolysis, and the transmission electron microscopy(TEM) results showed that carbon nanotubes were partly coated with TiO2. X-ray photoelectron spectroscopy (XPS) results of purified carbon nanotubes indicated that there were some polar oxygenated groups such as C–O, C=O and O–C=O which might stimulate formation of the composites, and enhance the interfacial combination of TiO2 with carbon nanotubes. The formation of TiO2 and its compounding with CNTs happened almost simultaneously in this process. The method is a convenient route to fabricate CNTs-based TiO2 composites with different ratios. [Copyright &y& Elsevier]