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Volume 64, Issue 9
Displaying 1-7 of 7 articles from this issue
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Comprehensive Papers
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Tsuyohiko FUJIGAYA, Naotoshi NAKASHIMA2007 Volume 64 Issue 9 Pages 539-552
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSBecause of the insolubility of carbon nanotubes (CNTs), chemical, biochemical, biological and medical applications using these materials have been rather limited. Soluble carbon nanotubes are of interest as nanomaterials in such fields. In this comprehensive paper, we describe i) strategies for the individual solubilization of CNT, especially for single-walled carbon nanotubes (SWNTs) in water or organic solvents and ii) the fundamental applications of the solubilized CNT.
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Original Papers
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Tomonaga UENO, Yuji HIGASHIO, Tomoyuki ISHIKAWA, Kunihiko TAKEDA2007 Volume 64 Issue 9 Pages 553-560
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSThe thermal degradation of an immiscible alloy, polycarbonate/acrylonitrile butadiene styrene copolymer (PC/ABS), was studied in comparison with that of industrialy used polyphenylene ether/high impact polystyrene (PPE/HIPS), a typical miscible alloy. Alloys of five different compositions were subjected to TGA, DTG, and pyrolysis-gas chromatography-mass spectrometry. A simple additivity was noted in the thermal degradation of PC/ABS alloys: deviation from the calculated values was larger with PPE/HIPS alloys than with PC/ABS alloys. In particular, the degradation of PC was accelerated for alloys with lower PC contents. The degradation of HIPS was retarded for the PPE/HIPS alloy. The degradation phenomena estimated from the scission products agree with the DTG data. The effect of mutual interaction between the polymers composing the alloy on thermal degradation was clearly shown.
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Kenjiro IGA, Tomonaga UENO, Kohshiroh MIZUNO, Tomoyuki ISHIKAWA, Kunih ...2007 Volume 64 Issue 9 Pages 561-567
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSWe have studied the flammability and “cage effect” of the immiscible alloy, PC (polycarbonate)/PLA (polylactic acid). Alloys whose compositions of PC and PLA were 60:40 and 30:70 by weight, respectively, were processed. The heat release rates of the alloys during the horizontal position test were similar to that of PLA. On the other hand, the flammability of the alloy was completely different from the values for PC and PLA in the vertical position test. In order to analyze the phenomena, we conducted thermal degradation tests conducted and obtained two-step degradation curves. The major scission products of the alloys were bisphenol-A originating from PC and acetaldehyde originating from PLA. The ratio of the scission products changed proportionately to the ratio of PC and PLA. These data suggested that the combustibility of PC/PLA alloy increases more than the values of PC and PLA individually due to the cage effect, by which PC protects the PLA drip from the alloy.
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Mitsukazu OCHI, Kazumi HASHIMOTO2007 Volume 64 Issue 9 Pages 568-574
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSEpoxy/silica hybrid materials showing no glass transition behavior have been reported to be prepared by in-situ polymerization of alkoxyl groups of 3-glycidyloxypropyl-trimethoxysilane (GPTMS) in epoxy resin oligomers. The effects of water content on the in-situ polymerization of GPTMS and the curing of epoxy oligomer were investigated in detail. The phase structure and dielectric properties of the hybrids were evaluated. It was revealed that with no added water the alkoxyl groups of the GPTMS react with the hydroxyl groups generated by the ring opening reaction of the epoxy groups. A homogeneous structure, where the inorganic component was uniformly distributed in the matrix, was formed. In the presence of the stoichiometric amount of water, on the other hand, inorganic siloxane networks were formed nearly completely through the sol-gel reaction. A heterogeneous structure, where a nano-meter-order inorganic phase was clearly separated in the epoxy resin matrix, was observed.
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Tomonaga UENO, Takafumi KAJIYA, Tomoyuki ISHIKAWA, Kunihiko TAKEDA2007 Volume 64 Issue 9 Pages 575-582
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSThe thermal degradation of polyesters (polylactic acid (PLA), polybutylene terephthalate (PBT), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN)) was studied. Thermogravinometry, pyrolysis gas chromatography/mass spectrometry, and elemental analysis were used in analyzing the scission products and the residues. The scission probability of each bond in polyester was calculated. The values obtained for the two bonds adjacent to C=O of PLA were 48% and 47%. On the other hand, those for the corresponding bonds were only 14% for PBT, most of scission (86%) occurring at the ester bond. The same tendency was observed for PET and PEN. The probabilities of the ester bond scission were, however, lower for PET and PEN, i.e., 59% and 49%, respectively. In conclusion, although different products and different probabilities were obtained for the polyesters, the thermal degradation path was considered to depend on 1) the relative stability of the scission product and 2) the formation of a pseudo-six-membered ring.
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Tomonaga UENO, Kohshiroh MIZUNO, Eiji KINOSHITA, Tomoyuki ISHIKAWA, Ku ...2007 Volume 64 Issue 9 Pages 583-589
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSThe thermal degradation of polyethylene naphthalate (PEN) was studied by measuring the scission products and by elemental analysis of the residue. The degradation temperature was similar to that of PE while the amount of residue was similar to those of PC and PPE. Low-boiling-point products such as acetaldehyde and carbon monoxide as well as monoesters and diesters were obtained as products. The atomic ratios of C, H, and O were calculated for PEN and compared with the accumulated values of the scission products and the residue. The ratios of H and O in the scission products and the residues was slightly lower than those of the values calculated for PEN. The scission route in the thermal degradation of PEN was considered to proceed via a pseudo six-membered ring intermediate, formed by the ester bond and the ethylene chain, to produce an acetaldehyde and a carbon monoxide. The radical generated on the naphthalene ring was important for the formation of the residue.
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Shinji HATAE, Yasumasa FUKUSHIMA2007 Volume 64 Issue 9 Pages 590-595
Published: 2007
Released on J-STAGE: October 06, 2007
JOURNAL FREE ACCESSMytilus edulis attaches to solid surfaces in turbulent environment by making a byssus, which contains 3,4-dihydroxyphenlalanine (DOPA). The DOPA residues are key components that are believed to be primarily responsible for underwater chemisorption of the adhesion proteins to substrates. This study describes the symthesis and adhesive properties of a pyrene-containing dipeptide, Boc-Lys(pyr)-DOPA. Boc-Lys(pyr)-DOPA forms fibrous-micelles by the self-assembly of hydrophobic pyrenes. The micelle surface constitutes of DOPA residues. Self-assembled Boc-Lys(pyr)-DOPA had good adhesive properties on various substrates. Our results advocate a new type of adhesive material and a may load to new material developments.
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