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Volume 38 (2011)
- Issue 5 Pages 149-
- Issue 4 Pages 112-
- Issue 3 Pages 77-
- Issue 2 Pages 46-
- Issue 1 Pages 1-
Volume 38, Issue 3
Displaying 1-6 of 6 articles from this issue
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Article
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Tatsuki Nyuui, Osamu Isawa, Atsuhiro Fujimori2011 Volume 38 Issue 3 Pages 77-82
Published: June 30, 2011
Released on J-STAGE: November 20, 2022
JOURNAL FREE ACCESSThe crystallization of perfluorinated polymers in the presence of polytetrafluoroethylene (PTFE) particle as nucleator was studied. Spherulitic textures of poly(tetrafluoroethylene-co-[perfluoroalkyl vinylether] (PFA) were examined in detail using polarized optical microscopy(POM). The PFA consisting of random comonomer units among the tetrafluoroethylene units crystallizes as spherulites composed of lamellae, although polytetrafluoroethylene usually forms extended-chain crystals (ECC) because of the rigid nature of 13/6 helices. The PFA spherulites obtained exhibit positive birefringence since the polymer crystal has a larger refractive index in the direction normal to the chain than that along it. Nucleator effect by adding PTEF particle induces PFA to rise a crystallization temperature. From the results of POM and atomic force microscopy (AFM), it is found that PFA particle become minute. These phenomena bring about epitaxial growth of polymer chain of PFA from nuleator surface.View full abstractDownload PDF (1497K)
Note
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Hiroshi Sato, Etsuo Sakai, Shingo Iida, Seiichi Hagiwara2011 Volume 38 Issue 3 Pages 83-85
Published: June 30, 2011
Released on J-STAGE: November 20, 2022
JOURNAL FREE ACCESSA conduction calorimeter with a thermally stable heat sink and six measurement cells have been designed and constructed. In order to make a compact calorimeter which is easy to operate in application to quality control of industrial materials such as cement, temperature of the aluminum heat sink was controlled directly using Peltier effect of Thermomodule. Temperature fluctuation of the heat sink was within ±0.1 ℃ during 8 days of continuous measurement accompanying large exothermic heat of reaction. Les than 40 μV/24h（1.38×10 －3℃）and 20 μVp-p（±0.69×10 －3℃）were achieved for base line drift and thermal noise, respectively. Both accuracy and reproducibility were estimated to be better than 0.5 %. Interference between the neighboring cells was negligible in simultaneous measurement of six samples. It was confirmed that the developed calorimeter was successfully applicable to measurement of industrial materials with extremely low reaction rate.View full abstractDownload PDF (635K)
Review
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Yasuo Saruyama2011 Volume 38 Issue 3 Pages 86-92
Published: June 30, 2011
Released on J-STAGE: November 20, 2022
JOURNAL FREE ACCESSBasic studies of temperature modulated DSC and temperature modulation method are summarized. These experimental techniques brought new abilities and ideas into the field of calorimetry and thermal analysis such as separation of the heat flow to the reversing and non-reversing components, frequency dependence, complex heat capacity, quasi-isothermal measurement and so on. These are explained in this paper with a brief description about a detailed mathematical model of temperature modulated DSC. An extension of temperature modulation technique to the slow dynamics is introduced.View full abstractDownload PDF (1132K) -
Susumu Hasegawa2011 Volume 38 Issue 3 Pages 93-98
Published: June 30, 2011
Released on J-STAGE: November 20, 2022
JOURNAL FREE ACCESSAmorphous solid dispersions provide an excellent way of increasing dissolution rates of poorly soluble drugs, but there may be concerns about stability. One way of assessing the stability of amorphous materials is the study of relaxation. In this study the relaxation at the surface of amorphous solid dispersions (SDs) was evaluated using inverse gas chromatography (iGC). A SD containing 70% indomethacin and 30 % PVP K30 was prepared by melt quenching. The SD was put into the iGC and heated to 17℃ below Tg for aging, during which decane was injected repeatedly. The retention volume of decane decreased with aging time, indicating that the sample relaxed on the surface during aging. During this period of storage no crystallization was observed by PXRD or DSC. Therefore, it is obvious that the change in this retention volume is due to the structural relaxation of the amorphous solid dispersion. The data of retention volume showed a good fit on a Kohlraush-Williams-Watts (KWW) equation and the indicator of the structural relaxation, τ, was estimated. This value was much lower than that of bulk relaxation estimated by DSC. Therefore, it can be concluded that the structural relaxation at the surface happens faster than that of the bulk.View full abstractDownload PDF (705K) -
Tsuyoshi Hoshino2011 Volume 38 Issue 3 Pages 99-106
Published: June 30, 2011
Released on J-STAGE: November 20, 2022
JOURNAL FREE ACCESSD-T fusion reactors need deuterium (D) and tritium (T) as their fuel. Since tritium does not exist in nature, it is necessary to produce tritium artificially by neutron irradiation of a lithium-filled blanket. Lithium titanate (Li2TiO3) has been recognized as one of the primary candidates for tritium breeder because of its good tritium release and its low activation. Addition of H2 to the inert sweep gas at the blanket has been proposed for enhancing the release of the generated tritium from the breeder material. However, Li2TiO3 is reduced in a H2 atmosphere at an operating temperature above 600℃, which will lead to degradation of the tritium release characteristics. The reduction of Ti in Li2TiO3 from Ti4＋ to Ti3＋ is accompanied by mass decrease due to decrease in oxygen content of Li2TiO3. In this study, development of Li2TiO3 with added Li was attempted to improve its resistance to deoxidization at high temperatures.View full abstractDownload PDF (1800K)
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2011 Volume 38 Issue 3 Pages 107-108
Published: June 30, 2011
Released on J-STAGE: November 20, 2022
JOURNAL FREE ACCESSDownload PDF (827K)
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