Growth of Carbon Nanotubes by Pyrolysis of Composite Film of Poly (Vinyl Alcohol) and Modified Fly Ash

We found carbon nanotube (CNT) materials by the pyrolysis of the composite film of poly (vinyl alcohol) (PVA) rein-forced with modified fly ash (FA) at 500°C for 10 min under 2 L/min flow of nitrogen. Fly ash was treated with 2M sodium hydroxide and used with PVA to fabricate the composite film by aqua casting. CNT materials were analyzed using XPS, Raman, SEM and TEM. The admixtures of CNT materials and FA are a potential filler material for fabri-cating composites with polymer and metal. The process is an eco-friendly recycling paradigm for using value-added advanced products for the proper management of sustainable waste materials, plastic and FA

Application of fly ash as a catalyst for synthesis of carbon nanotube ribbons

The larger diameter-based carbon nanotube (CNT) ropes and ribbons are currently synthesized by catalytic decomposition of hydrocarbons with transition metal-based catalysts e.g., Co, Ni, Fe and Mo at 1100–1200 ◦C, using chemical vapour deposition (CVD) and electric arc methods. We produced CNT ribbons by fly ash (FA) catalyzed pyrolysis of a composite film of poly (vinyl alcohol) (PVA) with FA at 500 ◦C for 10 min under a nitrogen flow of 2 L/min. Different geometrical structures, e.g.; knotted and twisted, U- and spiral-shaped CNT ribbons were observed in the images of scanning and transmission electron microscopy. The widths of the CNT ribbons measured varied in the ranges 18–80 nm. X-ray photoelectron spectroscopy analysis showed five types of carbon binding peaks, C–C/C–H (∼77%), C–O–H (∼9%), –C–O–C (∼5%), C O (∼5%) and –O–C O (∼3%). The ratio of intensities of G and D bands, IG/ID was 1.61 analysed by Raman Spectroscopy. CNT ribbons grown on the surface of FA have potential for the fabrication of high-strength composite materials with polymer and metal

Crystallization Kinetics of Polypropylene in Composite with Fly ash

Polypropylene (PP) composite materials reinforced with 20, 45 and 60 wt% of fly ash (FA) particles were prepared by injection moulding at 210 ‹C. Tensile strengths of the composite specimens were measured at 25, 50 and 70 ‹C using a controlled oven in Instron. At 25 ‹C, the composites suffered significant loss in strength, as much as 47%, whereas, at 50 and 70 ‹C, there was up to 15% gain in strength. Notched Charpy tests showed a maximum gain of 58 % impact energy for the composite with 45 % FA, tested at 70 ‹C over that of neat PP. In the dynamic mechanical analysis, it was observed that the addition of FA leads to the significant enhancement of both storage (EŒ) and loss modulus (E) of the composites compared to those of neat PP at a given temperature, supporting the view of the formation of interfacial interaction between the surfaces of PP and FA. The tangent ƒÂ curves of neat PP and composites showed a broader pattern of peak. The glass transition temperature (Tg) was assigned at 70‹C for neat PP and 72 to 73 ‹C for composites. Crystallization kinetics PP in composites has been studied non-isothermally and isothermally using differential scanning calorimetry at cooling/heating rates 10 ‹C, 15 ‹C and 20 ‹C per min between 200 ‹C to -30 ‹C. Whilst neat PP showed a mono modal ƒ¿ crystalline phase- only structure, presence of FA led to bimodal thermographs revealing partial transcrystallisation of ƒ¿ into ƒÀ, to maximum 14 %. The onset and peak crystallization temperatures of all samples decreased by approx 3 ‹C with each 5 ‹C /min increase in cooling rate. Parameters such as crystal growth rate, dimensions and activation energy were determined using a series of established models. The Avrami graphs showed that contrary to the published data, there are two sets of straight lines a) with a lower slope at low cooling rate and b) with a distinctly higher slope for high cooling rate. Activation energy of the materials reached a maximum at 45 % FA. In the study of isothermal crystallization kinetics, the lowest points of the exotherm peaks were shifted to higher crystallization times in the ranges of 0.75 - 1.50 min with the increasing of crystallization temperature (Tc) in neat PP and composites regardless of FA percentage addition

Hydroamidation of alkenes with 'N'-substituted formamides

Hydroamidation of olefins with N-substituted formamides is performed with dodecacarbonyltriruthenium (Ru₃(CO)₁₂) at 180⁰C under N₂ or CO atmosphere in toluene and in a series of ionic liquids. Yields of 99% with 94–97% exo selectivity are found in the addition of 'N'-methylformamide to 2-norbornene under CO both in toluene and in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [bmim][NTf₂]. The presence of CO or a phosphine is necessary for significant reaction to occur, with CO more effective than triphenylphosphine in all ionic liquids investigated. Reasonable yields are achieved at low pressures, in contrast to most reported hydroamidations. Conversion, 'exo'-selectivity, and selectivity fall with increasing steric bulk of the 'N'-formamide substituent, and disubstituted formamides are inactive. Of the terminal alkenes investigated, only styrene can be hydroamidated

Recycling of end-of-life melamine at 1 600°C for carbon dissolution into liquid iron

We produced the nano-structured graphitic materials by pyrolysis of end-of-life kitchen melamine-formaldehyde (MF) plate without externally supplied catalyst/additive at 1600 °C under nitrogen flow of 2 L/min. Different types of morphologies of carbon materials were observed under the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) such as, sheet, rod and porous particle. In Raman analysis, the material shows high level of crystallinity (~70% crystalline and remaining amorphous carbons) with high purity. We have applied this material in the carbon dissolution experiment with pure iron pellets under similar condition for a wide range of contact time. The carbon dissolution shows a linear relationship with contact time, and the maximum ~5.65% is determined for 45 min. The highly ordered spherical particles are assembled in the interfacial region of iron/MF. The high magnification of the spherical particle on SEM shows different types of phases containing carbon along with visible grain boundaries. The progression of carbon diffusion is found from the interface to the beneath of the surface in the polished iron pellet. The process is a promising recycling of sustainable material, end-of-life MF products for value-added advanced products as new carbon resource in steelmaking process for energy savings

Crystallization kinetics of PCL and PCL–glass composites for additive manufacturing

The non-isothermal crystallization kinetics of polycaprolactone (PCL) and PCL–glass composites, used in fused filament fabrication (FFF), was investigated. Films of PCL and PCL reinforced with powders of a bioactive glass, from the CaO.P2O5.MgO.SiO2 system, were prepared by solvent casting process. Crystal structure of the samples was examined by X-ray diffraction (XRD), and thermal properties were assessed by differential scanning calorimetry (DSC), at different cooling rates (5, 10, 15 and 20 C min-1). The DSC curves of non-isothermal crystallization showed a significant dependence of crystallinity (Xc) on the cooling rate. The relevant crystallization kinetic parameters were determined from DSC traces applying a combination of Avrami and Ozawa methods (Mo’s method), Jeziorny method and Friedman method. It was observed that the presence of inorganic particles within the polymeric matrix clearly influenced the composite crystallization. The addition of glass particles allowed a decrease in Xc and accelerated the PCL crystallization rate. The slower cooling rates tested proved to be suitable for the biofabrication of PCL–glass composites by FFF techniques.publishe