Radical Copolymerization of a Highly Fluorinated Cyclic Olefin Octafluorocyclopentene with Alkyl Vinyl Ethers

Summary Fluoropolymers are potential candidates for use in the fields of specific coating and lithography. Their versatility could be enhanced by increasing their glass transition temperature, T _g . In order to achieve this, the copolymerization of a highly fluorinated cyclic monomer, octafluoro-cyclopentene (OFCPE), with three kinds of alkyl vinyl ethers was investigated with a radical initiator in bulk. It was found that OFCPE and cyclohexyl vinyl ether (CHVE) copolymerized successfully, and the weight average molecular weight and T _g of the copolymer reached values of 12,000 and 124.9°C, respectively. Copolymer composition was close to a OFCPE:CHVE unit ratio = 0.5:0.5. The monomer reactivity ratios estimated by the Yamada-Itahashi-Otsu nonlinear least-squares procedure were found to be r _1,OFCPE = 0.005 ± 0.020 and r _2,CHVE = 0.154 ± 0.017.     

Characterization of chlorophyll pigments present in canola seed,meal and oil

Chlorophyll pigments present in canola seed, meal and crude and degummed oils were analyzed by high-performance liquid chromatography (HPLC) with a fluorescence detector. Chlorophylls a and b, low levels of pheophytin a, and occasionally traces of pheophorbide and its methyl ester were present in canola seed. Meals and oils contained magnesium-deficient chlorophyll pigments such as pheophorbide a, methylpheophorbide a, pheophytins a and b, and pyropheophytins a and b but not chlorophyll a or b. The amounts of chlorophyll pigments were oil > seed >> meal. Both crude and degummed oils contained pheophytin a and pyropheophytin a as main components, but the ratio of pyropheophytin a to pheophytin a was markedly higher in degummed oils. No pheophorbides were detected in degummed oils. These results suggest that oil processing steps such as extraction and degumming affect the composition of chlorophyll pigments. Publication No. 678 Canadian Grain Commission.     

Fabrication and photoactivities of spherical-shaped BiVO4 photocatalysts through solution combustion synthesis method

Spherical-shaped BiVO₄ photocatalysts were prepared by the solution combustion synthesis method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), nitrogen absorption for the BET specific surface area, field emission scanning electron microscopy (FE-SEM) and ultraviolet–visible diffraction reflection spectroscopy (UV–vis). The BiVO₄ crystallites show a monoclinic structure with diameter of about 400–600 nm. UV–vis diffusion absorption spectra indicate that the band gap absorption edge of pure BiVO₄ crystallites prepared by the SCS method and the SSR method are 523 nm and 540 nm, corresponding to the band gap energies of 2.45 eV and 2.40 eV, respectively. It is also found that the photocatalytic activity of degradation of methylene blue improves when the molar ratio of fuels to oxidizer is 5.     

High temperature annealing effects on carbon spheres and their applications as anode materials in Li-ion secondary battery

Carbon spheres (CSs) have been subjected to a high temperature annealing process at 2800 °C under an Ar atmosphere. These high temperature annealed carbon spheres (HTACSs) have been characterised by SEM, HRTEM, BET surface area, XRD, Raman, SQUID and TGA techniques. The study indicates that the original spheroidal morphology of CSs have been converted to polyhedral. The graphitic flakes possessing relatively short range order of which the original are composed of appear to have coalesced into more extended graphitic layers possessing long range order. Furthermore three dimensional interplanar graphitic ordering occurs. Charge-discharge capacity measurements have been performed on both carbon materials to access the potential of these materials in Li-ion secondary battery applications. The measurements indicate that HTACSs exhibit better performance than CSs in terms of greater reversible capacity and their longer plateau in voltage profiles.     

Shear-induced preferential alignment of carbon nanotubes resulted in anisotropic electrical conductivity of polymer composites

Multiwalled carbon nanotubes were used as filler to furan resin in the aim of producing an electrically conducting polymer composite that may be useful for electrode applications. The orientation of the nanotubes is controlled to prepare a composite with fillers unidirectionally oriented, which may result in higher electrical conductivity at one direction and at lower nanotube loading. Using the doctor blade technique, composite films were prepared and the alignment and its effect on the electrical conductivity of the composite were investigated. It was found that the doctor blade technique induced preferential alignment of the nanotubes in composite and a higher degree of alignment is achieved in composites with lower contents of nanotubes. Also, for low contents of nanotubes, the electrical conductivity of the composite with preferentially aligned nanotubes was up to a million times higher in the direction of alignment compared to that of the composite with randomly oriented nanotubes; however, at higher contents of nanotubes, this effect was diminished. The preferential alignment of the nanotubes also caused anisotropic electrical conductivity. The alignment and distribution is thought to create more junctions between nanotubes that resulted into the formation of more conducting channels in the polymer matrix parallel to blading direction.     

Synthesis and structural characterization of thin multi-walled carbon nanotubes with a partially facetted cross section by a floating reactant method

Here we describe synthesis of very unusual multi-walled carbon nanotubes through a catalytic chemical vapor deposition method using a floating reactant method and subsequent thermal treatment up to 2600 °C in a large quantity. Main characteristics of these nanotubes are (1) relatively wide distribution of diameters ranging from 20 to 70 nm and linear, long macro-morphology (aspect ratio >100), (2) highly straight and crystalline layers, (3) high purity through removal of metallic impurity, (4) very low interlayer spacing (0.3385 nm) and low R value (I_D/I_G = 0.0717), (5) high G′ intensity over intensity of G band (G′/G = 0.85) and strongly negative magnetoresistance value of −1.08% at 77 K and 1 T. The unusual microstructure of thin multi-walled carbon nanotubes with a partially facetted cross-sectional shape caused by thermal treatment is mainly ascribed to abrupt density changes (from 1.89 to 2.1 g/cm³) within a confined nanosized space, accompanying with the phase separation.     

Development of a high‐pressure air‐insulated 72/84‐kV disconnecting switch corresponding to bus‐transfer current switching

SF₆ gas has excellent dielectric strength and current interruption performance. For these reasons, it has been widely used for gas‐insulated switchgear (GIS). Today, such global environmental problems as global warming are important issues of concern. SF₆ gas is known as a greenhouse gas with a long atmospheric lifetime, and has global warming potential of 23,900. SF₆‐free 72‐kV GIS was recently developed by using high‐pressure air and a gas/solid hybrid structure. But an alternating current disconnecting switch (DS) has yet to be developed thus making this type of SF₆‐free 72‐kV GIS unsuitable for double bus‐bar application. Consequently, the development of a high‐pressure air‐insulated DS corresponding to bus‐transfer current switching has been expected. The bus‐transfer current is the highest among all current interruption requirements for the DS. To develop an alternating current DS, efforts must be made to reduce arcing damage to the electrode. This paper describes the fundamental characteristics of current interruption in the plain break type and the magnetic field driven type. Then, average arcing time of the magnetic field driven type was estimated by magnetic flux density. Finally, two types of DS, which were a high‐speed plain break and a low‐speed magnetic field driven, were confirmed to comply with bus‐transfer current switching requirements on JEC standard. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 48–55, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20595     

Energy saving performance of distributed heating and cooling system

An advanced distributed heating and cooling system utilizing small‐scale high‐performance heat pumps was designed to replace the central heating and cooling system for the AIST laboratory buildings, which have a total floor area of 36,100 m², of which 20,100 m² is occupied by laboratories. In the old system, the total primary energy required for hot water was 44 TJ, and it was 12 TJ for chilled water in FY 2001. The new system is composed of small‐sized high‐performance heat pumps, with an average coefficient of performance (COP) of 3.1. After the reconstruction, the energy consumption was reduced to 37%, and with a total energy saving of 44 TJ for one year. The total CO₂ emission is estimated to be 26%, a reduction of 3000 tons per year. The energy saving is caused by the high‐performance small‐scale heat pumps, the high‐performance total system design that takes laboratory into account, and the suitable operation of the system. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 46–53, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.20977     

Synthesis and radical polymerization of end-allenoxy polyoxyethylene macromonomer

Poly(ethylene glycol) allenyl methyl ether (2) was prepared by the reaction of poly(ethylene glycol) monomethyl ether (the number average molecular weight (M_{n) = 550}) with propargyl bromide, followed by the base-catalyzed isomerization reaction. Functionality of end-allenyl groups in the obtained macromonomer was determined as 92% (from ¹H-NMR). The radical polymerization of 2 was carried out in bulk and in benzene at 60 or 120°C to yield a polymer with poly(ethylene glycol) side chains. For instance, a polymer (3, M_n = 3900) was obtained in 39% yield by the polymerization of 2 in bulk at 60°C for 48 h using 6 mol% of α,α′-azobisisobutyronitrile (AIBN). The obtained polymer was soluble in organic solvents as well as water.