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1.
Hiroto Kudo Nobuhito Ito Keiji Nakajima Masami Ochiai Tadatomi Nishikubo 《Journal of polymer science. Part A, Polymer chemistry》2007,45(19):4421-4429
The polyaddition of fluorine‐containing bis(epoxide)s and fluorine‐containing triazine di(aryl ether)s were examined to give the corresponding fluorine‐containing poly(cyanurate)s. It was observed that the synthesized fluoropolymers had good thermal stabilities and good film‐forming properties. The glass transition temperatures (Tg's) and refractive‐indices (nD's) of synthesized polymers were determined by differential scanning calorimetry and ellipsometry, respectively, and it was found that the values of Tg's and nD's were supported by their fluorine containing ratios and skeletons. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4421–4429, 2007 相似文献
2.
Kazuaki Okamoto Suprakas Sinha Ray Masami Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2003,41(24):3160-3172
A series of new poly(butylene succinate) (PBS)/layered silicate nanocomposites were prepared successfully by simple melt extrusion of PBS and organically modified layered silicates (OMLS). Three different types of OMLS were used for the preparation of nanocomposites: two functionalized ammonium salts modified montmorillonite and a phosphonium salt modified saponite. The structure of the nanocomposites in the nanometer scale was characterized with wide-angle X-ray diffraction and transmission electron microscopic observations. With three different types of layered silicates modified with three different types of surfactants, the effect of OMLS in nanocomposites was investigated by focusing on four major aspects: structural analysis, materials properties, melt rheological behavior, and biodegradability. Interestingly, all these nanocomposites exhibited concurrent improvements of material properties when compared with pure PBS. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 3160–3172, 2003 相似文献
3.
A liquid chromatography-mass spectrometry (LC/MS) method was developed for the separation and determination of linear alkylbenzenesulfonates (C10-C14 LAS) in environmental water samples using a hydrophilic polymer column (Shodex Mspak GF-310 4D). This method involves a solid-phase extraction of the LAS samples with a Sep-Pak PS-2 cartridge. The LAS components were separated on the column with a mobile phase of 29% (w/v) acetonitrile-water containing 0.8 mM di-n-butylammonium acetate and 0.2 M acetic acid, and were detected by mass spectrometry with electrospray ionization. Detection limits of the developed method based on selected ion monitoring (SIM) technique for the C10-C14 LAS standards were 13-47 ng L(-1). The concentrations of the C10-C14 LAS in the environmental water samples ranged between 5-317 microg L(-1) for a river water sample and 0.4-6.4 microg L(-1) for a seawater sample. Linear relationships between the logarithms of retention factors and the alkyl chain lengths for each phenyl positional isomer of LAS could successfully be used for the identification of the isomer peaks. 相似文献
4.
Separation of fulvic acid from soil extracts based on ion-pair formation with a cationic surfactant.
Masami Fukushima Atsunori Kikuchi Kenji Tatsumi Fumiko Tanaka 《Analytical sciences》2006,22(2):229-233
A novel method for separating fulvic acid (FA) from soil extracts is proposed. The FA, defined as the acid-soluble fraction of an alkaline extract of soil, was separated based on the precipitation of an ion-pair with a cationic surfactant, such as domiphen bromide. The precipitate was dissolved in aqueous HCl to produce H+ -type FA and a surfactant chloride (SUR-Cl). SUR-Cl, in the aqueous solution, was removed by extraction with CHCl3. After the aqueous phase was passed through a cation-exchanger (H+ -type), H+ -type FA (FA-SUR) was obtained as a powder by lyophylization. The chemical characteristics of FA-SUR were compared with an FA sample separated according to the method of the International Humic Substances Society using a DAX-8 resin (FA-DAX). The oxygen content, O/C atomic ratio and total acidity of the FA-SUR were significantly larger than the corresponding values for FA-DAX. The solid-state CPMS 13C NMR spectra indicated that the higher oxygen content of the FA-SUR could be due to alcoholic hydroxyl groups and polysaccharides as well as carboxylic groups. These results show that FA-SUR is more polar and hydrophilic than FA-DAX. 相似文献
5.
Anionic cycloaddition of methyl isocyanoacetate to diethoxyacetonitrile afforded methyl 5-diethoxymethylimidazole-4-carboxylate, a useful imidazole nucleus with two different functional groups. 相似文献
6.
Chanmahasathien W Li Y Satake M Oshima Y Ishibashi M Ruangrungsi N Ohizumi Y 《Chemical & pharmaceutical bulletin》2003,51(11):1332-1334
A new prenylated xanthone, 1,3,5,6-tetrahydroxy-4,7,8-tri(3-methyl-2-butenyl)xanthone (1), was isolated from the wood of Garcinia xanthochymus together with a known xanthone, garciniaxanthone E (2). Their structures were determined by spectroscopic analysis. Compounds 1 (3 microM) and 2 (10 microM) elicited marked enhancement of nerve growth factor-mediated neurite outgrowth in PC12D cells. 相似文献
7.
Takayuki Otsu Masami Yamaguchi 《Journal of polymer science. Part A, Polymer chemistry》1968,6(11):3075-3085
A study of the polymerization of methyl methacrylate initiated by the binary systems of some activated metals and organic halides has been made. It was found that the initiator activities of these systems were greatly dependent on the kind and the preparation or activation method of the metals (i.e., oxidation potential, surface area, and purity), and also on the kind of organic halides (i.e., bond-dissociation energy of their carbon–halogen bonds). From the kinetic studies of the polymerization at 60°C with the system reduced nickel–carbon tetrachloride, the rate of polymerization was found to be proportional to the monomer concentration and to the square root of concentration of both nickel and carbon tetrachloride at the lower concentration range of carbon tetrachloride, indicating that the system induced the radical polymerization. A similar conclusion was also obtained from the copolymerization with styrene with this system at 60°C, i.e., the resulting copolymer composition curve was in agreement with that obtained with azobisisobutyronitrile (AIBN). The apparent overall activation energy for the methyl methacrylate polymerization with this system was estimated to be 7.5 kcal/mole, which was considerably lower than that with AIBN. On the basis of the results obtained, an initiation mechanism for the polymerization with these initiator systems is presented and discussed. 相似文献
8.
Tetsuo Miyazaki Shigeru Nagasaka Isao Maeda Takuro Matsumoto Shinji Koyama Seiji Kodama Masami Watanabe 《Radiation Physics and Chemistry》1996,47(6):817-819
Emission from high-energy-electron-irradiated golden hamster embryo (GHE) cells has been studied over the temperature range 12–300 K both by a one-shot-single-photon-counting method and by photocurrent measurements with an oscilloscope. Emission from the irradiated phosphate buffered saline (PBS) also has been studied. The emission spectra from PBS at 12 and 77 K show a maximum around 330 and 380 nm, respectively, which are the same spectra as those from irradiated pure H2O. The emission from irradiated GHE consists of the new band at 480 nm in addition to the emission from H2O. The 480 nm emission is observed at the temperature range of 12–300 K, though the emission at 300 K is much lower than that at low temperature. The 480 nm emission is ascribed to the transition from excited organic substances in GHE cells. The intensity of 480 nm emission at 300 K increases linearly with increasing irradiation-dose in the range of 11–600 Gy. 相似文献
9.
Hamao Umezawa Tomohisa Takita Yukio Sugiura Masami Otsuka Susumu Kobayashi Masaji Ohno 《Tetrahedron》1984,40(3):501-509
Biosynthetic intermediates and synthetic analogues of bleomycin (BLM) have been investigated for their metal binding, dioxygen activation, and DNA cleavage. Molecular O2 was activated by the Fe(II) complex of a synthetic model ligand. Nucleotide sequence specificities in DNA cleavage by the BLM-Fe(II) and deglyco-BLM-Fe(II) complexes were almost identical. It has been shown that (1) the β-aminoalanine-pyrimidine-β-hydroxyhistidine portion of BLM is essential for the metal binding and dioxygen activation and (2) the bithiazole moiety contributes to the specific binding to guanine base of DNA. 相似文献
10.
The cycloaddition reaction of N-ethoxycarbonyl-1H-azepine with 2,5-dimethoxycarbonyl-3,4-diphenylcyclopentadienone gave anti-endo [4+2]π and exo [6+4]π cycloadducts. These structures were fully identified by X-ray crystallographic techniques. Mechanism for their cycloaddition reactions are also discussed. 相似文献