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Volume 41, Issue 12
Displaying 1-9 of 9 articles from this issue
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Jie CHEN, Zhanxun CHEN, Zhizhon WANG1984 Volume 41 Issue 12 Pages 705-710
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe composition and the structure of plasma-polymerized tetrafluoroethylene (PPTFE) in thin film, which was formed in the glow region, were investigated by means of X-ray photoelectron spectroscopy (XPS). The ratio of fluorine to carbon (F/C) in the PPTFE was determined to be 1. 42 by use of intensities of the F18 and C18 spectra. The curve resolution of the broad signal for C18. resulted in five kinds of peaks with different C18, electron binding energies : 284. ± 0. 4, 287. 0± 0.3, 289. 0± 0.2, 291.5± 0.2, and 293.6± 0.1 eV. In order to assign the C18 spectra, the Cls energy shifts (ΔE (C18)) for the specified carbon atoms of several model compounds were estimated by using (i) an electrostatic potential model based on the CNDO/2 calculation of the atomic charges and (ii) an electronegativity parameter method. An empirical equation concerning the increment of C18 electron binding energy due to fluorine substitution was derived from the theoretical calculation. By reference to this empirical equation, it was confirmed that the PPTFE includes highly branched and cross-linked segments.View full abstractDownload PDF (919K) -
Kazuto INOUE, Yoshio IMAI, Yoshihito OSADA1984 Volume 41 Issue 12 Pages 711-716
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSAromatic azo polymers were prepared by oxidative coupling polymerization of 3, 4′- and 4, 4′-diamine derivatives of bibenzyl, trans-stilbene, and tolan; inherent viscosities of two bibenzyl-containing azo polymers and four azo polymers having stilbene and tolan structures are 1.0-1.8 and 0.3-0.4dl/g, respectively. These aromatic azo polymers are brown-black powders, and are soluble in hot methanesulfonic acid but insoluble in all other organic solvents including N, N-dimethylacetamide. The 4, 4′-series azo polymers are crystalline, while 3, 4′-series polymers are amorphous. The aromatic azo polymers are infusible and lose 10% weight above 400°C and 450°C in air and nitrogen, respectively. The thermal stability of both 3, 4′- and 4, 4′-series polymers increases in the order of the bibenzyl-containing polymers<the trans-stilbene-containing polymers <the tolan-containing polymers. The rate constants for the photoisomerization of the aromatic azo polymers with visible light were determined in methanesulfonic acid at 30°C.View full abstractDownload PDF (918K) -
Toshio KITAO, Yoshiharu KIMURA, Takashi KONISHI, Mikio ARAKI, Yoshihis ...1984 Volume 41 Issue 12 Pages 717-725
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA high molecular weight poly (glycolic acid) was prepared by the ring-opening polymerization of glycolide and then stabilized by capping the therminal hydroxyl groups with acetic anhydride. The thermal and the rheological properties were evaluated by DTA and shear experiments : DTA trace merely informed the transition phenomena (Tg=37 and Tm=224°C), whereas the extraordinary apparent activation energy of viscous flow, 32 kcal/mol., computed from viscosity data implied that the molecular decomposition possibly occurred in Couette viscometer. A smooth and steady melt spinning could be carried out at 240°C using a laboratory spinning instrument. After being drawn in water at 65°C and annealed at 190°C for 10mins, the PGA fibers of which tensile strength was 1 GPa and elastic modulus was 14 GPa were allowed to stand in pseudo extra-cellular fluid (PECF; a buffer solution of which pH is 8.2), saline, distilled water, and ethanol for in vitro hydrolysis. In aqueous solutions, many fine cracks were generated on the fiber surface in the early stage, and then the etching propagated on to cover the entire surface. Finally many fine fragments were dropped out of the fibers resulting in the reduction of the fiber thickness. The tensile properties reflected these decomposition behavior. In ethanol, however, no detectable change was observed both in appearence and in mechanical properties throughout the entire period of the hydrolysis.View full abstractDownload PDF (1725K) -
Kunio FURUSAWA, Noribumi WATANABE, Yoshiaki WATANABE1984 Volume 41 Issue 12 Pages 727-732
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe flocculation behavior of platelet particles induced by non-adsorbing polymer has been studied using the tungstic acid sol (t-sol) plus the poly (ethylene oxide) (PEO) system. The PEO molecules do not adsorb alone on the t-sol particles, and do not show any influence on the flocculation behavior of the t-sol. However, the t-sol involving particles covered by other polymer (e. g., polyacrylamide (PAAm)) layers has flocculated effectively by the PEO, especially by changing the solvency of the PEO solution. Flocculation measurements are made at 25°C, 40°C and 50°C at various electrolyte (MgSO4) concentrations. These results indicate that the present flocculation has occurred by the cohesive energy of the PEO through the adsorption layers of PAAm, and has been not caused by the depletion layer effect of the non-adsorbing polymer.View full abstractDownload PDF (1340K) -
Kazuo ARAKAWA, Tadao SEGUCHI1984 Volume 41 Issue 12 Pages 733-738
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSOxygen consumption and yield of oxidation products during γ7-irradiation are studied on polyethylene (PE), and ethylene-propylene copolymer (EPR) using a gas chromatography. Polymer films of different thickness are irradiated in oxygen by 60Co γ-rays up to 200kGy with a dose rate (I) of 2kGy/h-20kGy/h at room temperature. The G-values of oxygen consumption decrease with film thickness and with dose rate, showing that oxidation is controlled by diffusion of oxygen. The amount of oxygen consumption is in excellent agreement with the values calculated by using a diffusion control model. Oxidation layer thickness of PE and EPR film is apparently proportional to I-1/3.View full abstractDownload PDF (1009K) -
Kazuko OHTA, Kuniko URANO, Kazuo KAWAHARA1984 Volume 41 Issue 12 Pages 739-744
Published: December 25, 1984
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSThe ultrasonic degradation of pullulan in solution has been investigated. A few samples of pullulan is irradiated with ultrasonic waves in 0.5% aqueous solution contained 0.9% NaCI at 30°C, and average molecular weights and molecular weight distributions of degraded pullulan samples are evaluated by gel filtration method. <Br>Observed results on the decrease of the average molecular weight and on the changes in the molecular weight distribution indicate the following characteristics in the ultrasonic degradation of pullulan. The degradation proceeds with different behaviors in different regions of the molecular weight (M). Pullulan of high M degrades very rapidly and yields a product having wide molecular weight distribution with a peak around M=3×104, then degrades very slowly and yields a final product of low M with a peak around M=3-5×108. For M below 20×104, the degradation is apparently a first-order reaction and the apparent rate constant decreases with decreasing M. Pullulan with M below 3-5×108 shows no degradation.
The results are compared with those of dextran previously reported.View full abstractDownload PDF (1003K) -
Nobuyoshi SASAKI, Tetsuo YOKOYAMA1984 Volume 41 Issue 12 Pages 745-753
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe formation of hydrogen (H) bonds in the poly (methacrylic acid) -poly (vinyl methyl ether) (PMAA-PVME) polymer complex and its thermal behavior were studied by IR spectroscopy and dynamic mechanical measurements. The two PMAA with different tacticities (at-PMAA: S, 53.3; H, 42.4; I, 4.3 and st-PMAA: S, 76.3; H, 20.2; I, 3.5) were used. The molar ratios of PMAA/PVME in the polymer complexes precipitated from aqueous solutions were 50/50 for at-PMAA and 40/60 for st-PMAA. In the case of st-PMAA, the polymer complexes were obtained as precipitates in the fiber forms. At the same composition ratios as described above, the temperatures of primary dispersion of the films of the both PMAA series which were cast from methanol agreed with the dissociation temperatures Td of the H bonds, respectively. This fact suggests the glass transition is mainly governed by the breakdown of H bonds. The films in the st-PMAA series showed higher H bonding abilities and Td, which was attributable to the structural regularity of the polymer complexes. The energy differences of the H bonds between carboxyl and ether oxygen and between carboxyl and carboxyl (dimeric form) were 13.8 kJ mol-1 in the 50/50 film for at-PMAA series and 20.9 kJ mol-1 in the 40/60 film for st-PMAA series.View full abstractDownload PDF (1451K) -
Sadaatsu YAMAGUCHI1984 Volume 41 Issue 12 Pages 755-757
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe width of sheaf-like bands observed on poly (tetrafluoroethylene) surfaces depends on cooling rate. The width is ca. 0.12μm when the polymer sheet is rapidly cooled in an atmosphere of -20-25°C. Several narrow bands appear on each of sheaf-like bands grown at low cooling rates. Their widths are ca. 0.12μm, and agree with those for rapid cooling. From this agreement it is concluded that the sheaf-like band obtained at a low cooling rate consists of the narrow bands.View full abstractDownload PDF (691K) -
Hirokazu HASEGAWA, Takeji HASHIMOTO1984 Volume 41 Issue 12 Pages 759-762
Published: December 25, 1984
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPrior to the small-angle neutron scattering study on the conformation of block polymer chains in the domain space, the state of mixing of two block polymers, an ordinary polystyrene-polyisoprene diblock polymer and a poly (deuterated styrene) -polyisoprene diblock polymer with a different molecular weight and composition, was investigated by a small-angle X-ray scattering (SAXS) technique. Only one kind of domain structure was observed for each blend, and the domain spacings obtained by SAXS were proportional to the two-thirds power of the number-average molecular weight of the blends (reduced to non-deuterated block polymer). The volume fractions of polystyrene domain in the blends evaluated by computer simulation of SAXS profiles well agreed with the values estimated from blend composition. All these facts suggest the molecular mixing of the two block polymers in the domain space.View full abstractDownload PDF (509K)
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