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Volume 49, Issue 5
Displaying 1-7 of 7 articles from this issue
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Fluorescence in Plastics and in SolutionsKazuo AMANO, Tadao HINOHARA, Kohji MATSUI1976 Volume 49 Issue 5 Pages 271-276
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSRecently, the fluorescent agents are widely used as the whitening agent for the plastics. The behavior of the fluorescent agent in the plastics should be different from that in the fluid solution, and to make this difference clear is important for the practical use of the fluorescent agent to plastics. It is the object of this investigation to clarify the difference between the nature of the fluorescence in the fluid solution and in the solid plastics.
The fluorescent agents employed here are four derivatives of 7-amino coumarin. Cyclohexane and polystyrene are used as the non-polar medium, and ethyl ether and polycarbonate as the polar medium. These two pairs of medium have nearly equal value of dielectric constant and may be favourable for the study of the effect of medium on the nature of fluorescence.
The absorption and fluorescence spectra in the solid plastics are essentially the same as in the solution except for the slight red shift. The red shift of the absorption and fluorescence band due to the increase in the polarity of the medium, which is generally observed in the fluid solution, are also observed in the solid plastics. These results indicate that the conditions of the fluorescent molecule in the plastics are nearly identical with that in the solution. The fluorescence intensity is sensitively affected by the variation of the nature of the plastics. The fluorescence intensities in plastics plotted against correspondent intensities in cyclohexane give the straight line, and the slope of this line is found to depend sensitively on the sort of the plastics. The value of this inclination should play an important role in the practical application of the fluorescent agent to plastics.View full abstractDownload PDF (732K) -
Hitoshi TAKEBAYASHI, Masumi KOISHI1976 Volume 49 Issue 5 Pages 277-282
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSStainless modified-kaolins were prepared by using a centrifugal rotating-type ball mill. In these experiments, the mechanochemical effects were clearly observed during the grinding of kaolin in water at various rotating number, such as 230,350,500 and 650 rpm.
Kaolin was mechanically ground by alumina balls and, at the same time, stainless steel lining wall was gradually wore away by hard strikes with both alumina balls and kaolin particles.
From the X-ray diffraction, fluorescence X-ray analysis, electron microscopy, specific surface area and electrophoresis it would be concluded as follows :
(1) Kaolin was modified by physical adsorption of stainless steel powder on its surface.
(2) Final reaching values of both the grinding degree of kaolin and the content of stainless steel powder on kaolin surface were correlated with rotation number. As the results, they were represented as “(grinding degree) _??_ (rotation number) 1/2” and “log (content of stainless steel powder) _??_ (rotation number)”.
(3) Zeta potential of stainless modified-kaolin recognized to be linearly decreased with the increase of either the grinding degree of kaolin or the content of stainless steel powder on kaolin surface.View full abstractDownload PDF (1379K) -
Hitoshi TAKEBAYASHI, Hisao HIDAKA, Masumi KOISHI1976 Volume 49 Issue 5 Pages 283-289
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSIn a previous study, it is found out that the stainless modified-kaolin as a pigment was easily prepared by a new type centrifugal rotating-ball mill. Moreover, these experiments were conducted to determine the optimum rotating number for a grind of kaolin in water.
As the results, the most suitable data in both the grinding degree of kaolin and the content of stainless steel powder on kaolin surface were obtained at 650 rpm of rotating number.
In this paper, the authors studied on the determination of optimum alumina ball number in preparation of stainless modified-kaolin.
From the X-ray diffraction, fluorescence X-ray analysis, electron microscopy and electrophoresis it would be concluded as follows :
(1) Final reaching values of both the grinding degree and the content of stainless steel powder on kaolin surface were linearly correlated with alumina ball number in mill. The efficiencies of above two values were increased with the decrease of alumina ball number within the experiment conditions.
(2) The relative grayish color strengths of final stainless modified-kaolin powder increased slightly with the decrease of alumina ball number.
(3) Zeta potential of stainless modified-kaolin showed the inclination of linear decrease with the increase of either the grinding degree of kaolin or the content of stainless steel powder on the kaolin surface. However, the dependences of alumina ball number on them were not clearly appeared.View full abstractDownload PDF (1793K) -
Toshio KUBOTA, Toshio UEDA1976 Volume 49 Issue 5 Pages 290-296
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe thermal stabilities of polyester urethanes synthesized by the reaction of polyesterpolyol and toluenediisocyanate (TDI) adduct, polyesterpolyol and xylenediisocyanate (XDI) adduct, and polyesterpolyol and hexamethylenediisocyanate (HMDI) adduct were studied. The test specimens were heated at 175°C for 100 hours in air or nitrogen flow, and weight losses, amount of evolved carbon dioxide, changes in elementary compositions, and IR spectra were measured.
The results were summarized as follows :
In nitrogen flow, only slight weight losses were observed when every type of polyurethanes were heated at 175°C, and the thermal stability were shown to be XDI-polyurethane > HMDI-polyurethane > TDI-polyurethane. This result coincide with the published data on the thermal stability of polyester urethanes from various diisocyanates.
In air flow, however significant decrease in IR spectral absorptions of amide II and III for urethane bond, considerable extent of weight loss and carbon dioxide evolution were observed when HMDI-polyurethane and XDI-polyurethane were heated at 175°C. To the contrary, TDI-polyurethane was shown to be thermally stable. From the results obtained, it was considered that the oxidation accampaning with the substraction of hydrogen atom from α-position carbon bonded with nitrogen atom of urethane bond might be responsible for the thermal oxidation of polyurethanes. Therefore, HMDI-polyurethane and XDI-polyurethane are easily oxidized when heated in air, but TDI-polyurethane will be hardly oxidized because its α-position carbon atom bonded with nitrogen atom of urethane bond constitutes a part of benzene ring.
From the thermogravimetric curves, activation energy (E) was calculated.View full abstractDownload PDF (1128K) -
Shigeo MINE1976 Volume 49 Issue 5 Pages 297-302
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
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Yasushi MATSUMARU1976 Volume 49 Issue 5 Pages 303-315
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
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Yasuhiro SUZUKI, Kyoichi SHIBAYAMA1976 Volume 49 Issue 5 Pages 316-324
Published: May 20, 1976
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDownload PDF (1388K)
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