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Volume 49, Issue 12
Displaying 1-12 of 12 articles from this issue
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Akihiro SUZUKI, Fumi HOSAKA, Toshio KUNUGI1992 Volume 49 Issue 12 Pages 947-951
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe zone-drawing method has been applied to poly (vinyl chloride) fibers in order to improve their mechanical properties. In the present study, the as-spun poly (vinyl chloride) fibers containing no plasticizer or filler were used. To determine the suitable conditions for first and second zone-drawings (ZD-1 and ZD-2), the zone-drawings were examined over a drawing temperature region of 90°C to 110°C and under an applied tension from 0.1 MPa to 23.5 MPa. The relation between draw ratio and birefringence was found to be linear in spite of different drawing conditions. Young's modulus of the fibers also was proportional to the value of birefringence. Further, the suitable conditions were determined as follows: 90°C and 3.9 MPa for ZD-1 and 100°C and 19.6 MPa for ZD-2. Young's modulus and tensile strength increased with processing. The ZD-2 fiber has Young's modulus of 6.7 GPa and a tensile strength of 0.36 GPa. The dynamic modulus (E′) also increased with processing, and the at 110 Hz and 25 for the ZD-2 fiber reached a high value of 8.9 GPa. The E′ stayed constant up to temperatures near Tg, and then it drastically and irreversibly decreased in the glass transition region. This suggests that the chain segments flow rapidly above Tg.View full abstractDownload PDF (832K) -
CTBN Block CopolymersMitsukazu OCHI, Minoru UNO, Kenji MIMURA, Takanori KAMOTO, Toshio TAGA ...1992 Volume 49 Issue 12 Pages 953-960
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSBisphenol-A type epoxy resin was modified with Aramid-CTBN block copolymer to improve the toughness of the cured resins. By the modification, glass transition temperature of the systems was increased from 180 to 206°C and the values of impact strength and fracture toughness were also increased more than 30% over those of the unmodified system. Such behavior is explained as a result of the combined action of the dissolution of Aramid block and the phase separation of CTBN block in the epoxy matrix. The improvement of toughness for the cured resins was strongly dependent on the solubility of Aramid block into the epoxy matrix. In the modified systems in which the Aramid block of the copolymer has high solubility, the CTBN block forms micro-phase separation and is uniformly dispersed in the matrix. The toughness of this system increased significantly with the addition of the block copolymer. On the other hand, when the Aramid block has low solubility, the block copolymer itself forms micro-phases and is non-uniformly dispersed. The improvement of toughness in this systems was very small.View full abstractDownload PDF (1856K) -
Seiji TONE, Akira NAKATA, Hiroshi MORI, Naoki YAMAMOTO1992 Volume 49 Issue 12 Pages 961-967
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPoly (methyl methacrylate) -graft-polydimethylsiloxane was synthesized by the copolymerization of methyl methacrylate (MMA) with macromonomer having a methacryloyl group at one end of polydimethylsiloxane (PDMS). The fibers formed by melt spinning of this copolymer were bundled up. After being impregnated by the methacrylate compounds, they were polymerized to obtain a shaped article. The focus of this paper is investigation of the relation between micro phase separation state and oxygen permeability. Small angle X-ray scattering showed that the domains of PDMS were oriented to the direction of the fiber axis in proportion to the increase of the draft ratio (=winding speed/extruding speed). The value of oxygen permeability parallel to the direction of the fiber axis was nearly equal to the value calculated on the assumption that continuous phase would be formed by PDMS domains parallel to the direction of the fiber axis. The oxygen permeability, parallel to the direction of the fiber axis was higher than that of non-oriented sample. It was clear that the oxygen permeability of the shaped article could be controlled by its morphology.View full abstractDownload PDF (1649K) -
Toshihide INOUE, Noriaki GOTO, Norikazu TABATA, Toru YAMANAKA, Tatsund ...1992 Volume 49 Issue 12 Pages 969-973
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSHigh molecular weight polyarylates derived from methylhydroquinone and 4, 4′-diphenyldicarboxylic acid (CH3-HQ/BB) were prepared by melt polymerzation, followed by solid-state polymerization. Injection molded test pieces of CH3-HQ/BB showed high flexural modulus (30.8 GPa, 0.8 mm thickness). SEM of the fractured injection molded test pieces showed few needle-like fibrils but showed plate-like structures. DSC thermograms of CH3-HQ/BB showed two endotherm peaks (304-310 and 362-370°C). The lower endotherm peak was confirmed to be a crystal-crystal transition by the X-ray diffraction patterns.View full abstractDownload PDF (1140K) -
Hiroshi SAKAMI, Kaoru KAWASE1992 Volume 49 Issue 12 Pages 975-979
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPreparation conditions of fine layer-like pores in highly crystalline polypropylene (PP) films were investigated. The mixture of PP, paraffin (Pa), and polyoxyethylene stearyl ether (POS) were hot-rolled at various rolling rates and then Pa was extracted with organic solvent. The fine structure of these films was studied by measuring the apparent specific volume, the surface area using the N2 gas adsorption-desorption method and small angle X-ray scattering. PP films mixed with Pa of mixing ratios (in wt) (MR) from 0.40 to 1.25 showed layer-like pores, when they were rolled at rolling ratios of 5 to 15 at 125°C. A wide surface area of 270 m2/g was achieved under the conditions of MR=0.40 and a rollin ratio of 15. It was suggested that the micelle particles of POS were formed in Pa on cooling. At the same time, a regularly staked structure of PP lamellae with layer-like pores of 112Å and 60Å thick was formedView full abstractDownload PDF (929K) -
Shinsuke TAKEGAMI, Shoji TUJII, Hideki YAMADA1992 Volume 49 Issue 12 Pages 981-991
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPoly (1H, 1H, 2H, 2H-heptadecafluorodecylacrylate) grafted polydimethylsiloxane (P (V-17F) -g-PDMS) was synthesized by radical copolymerization of 1H, 1H, 2H, 2H-heptadecaflorodecylacrylate and polydimethylsiloxane macromonomer (Mn=10000) containing methacryoxy groups at one end. Pervaporation of ethanol/water mixtures was investigated using composite membranes consisting of graft copolymer and PTFE micr-porous membrane. The separation factor of ethanol to water increased with decreasing of feed temperature. Especially at 30°C, P (V-17F) g-PDMS membrane showed higher separation factor (αEtOH H2O=13.3 for 10 vol% ethanol aqueous solution) than that of PDMS membrane (RTV silicon rubber). The perfluoroalkyl groups are arranged compactly on the surface of membrane and so the surface becomes very water-repellent, and therefore the solubility (adsorption) of ethanol is increased and the separation factor increases. The separation factor for the aqueous solution containing various organic substance had a clear relation to the solubility parameter.View full abstractDownload PDF (1829K) -
Kiyoshi YONEZU1992 Volume 49 Issue 12 Pages 993-998
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe acetalizations of ethylene-vinyl alcohol copolymers (EVOH) containing 32 and 45 mol% ethylene were studied kinetically in homogeneous solution. The rate constant was independent of the ethylene content and was almost proportional to the concentration of HCl, on the assumption that the acetalization occurs only between intramolecular neighboring vinyl alcohol units. The rate of the acetalization with acetaldehyde was about 700 times that of the formalization in a dimethyl sulfoxide-water-methyl alcohol mixture. 1, 3-Butanediol was acetalized with various aldehydes as a model compound of EVOH in dimethyl sulfoxide-water-methyl alcohol mixtures. The ratio of the rate of the acetalization with acetaldehyde to the rate of the formalization was similar to that of EVOH. The acetalization was retarded by a small amount of water, especially in case of the formalization.View full abstractDownload PDF (1032K) -
Makoto KAWAGOE, Mikio MORITA, Sadaaki NUNOMOTO1992 Volume 49 Issue 12 Pages 999-1003
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSFatigue tests of poly (methyl methacrylate) (PMMA) were conducted under methanol environment at room temperature using solid cylindrical specimens which had been presoaked in methanol for various periods. A fatigue lifetime 10000 times that of the specimen without presoaking was obtained for the specimens presoaked for periods ranging 8-96 h. Presoaking for longer periods provided a fatigue lifetime only 100 times that of the untreated specimen. Scanning electron micrographs revealed that numerous cracks with fibril structure at their tips, formed by shear deformation, are developed on the surface of each specimen, showing the dramatic increase in the fatigue lifetime. The vestiges of shear flow and shear cracking are seen on its fracture surface. These microscopic observations indicate that the dramatic increase in the fatigue lifetime by presoaking treatment is a transitional process in the fracture mode from brittle fracture dominated by crack (craze) opening to ductile fracture following shear flow. This is brought about by both the softening of PMMA and the generation of internal compressive stress in the surface layer due to case II diffusion of methanol.View full abstractDownload PDF (1459K) -
Tatsuo IWASAKI, Yoshitsugu UEDA1992 Volume 49 Issue 12 Pages 1005-1010
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSVinyl monomers such as styrene, methyl methacrylate, acrylonitrile, and acrylamide were grafted onto nylon 6 fibers by a γ-ray pre-irradiaition technique in vacuum. The effect of various additives on the apparent percent graft as well as on the molecular weight and mole number of grafted vinyl polymer branch were investigated. The intrinsic viscosity [η] of the branch polymer was obtained by selective hydrolysis of the backbone nylon 6. The apparent percent graft of the grafted polystyrene increased by adding methanol, ethanol, acetic acid, or propionic acid to styrene monomer. The additive which behaved as a good swelling agent for nylon 6 and, at the same time, as a precipitant for polystyrene gave higher apparent percent graft. The apparent percent graft of methyl methacrylate monomer was also increased by adding methanol.View full abstractDownload PDF (1128K) -
Hiroshi YANAGISHITA, Takashi NAKANE, Hiroshi YOSHITOME1992 Volume 49 Issue 12 Pages 1011-1014
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSAsymmetric membranes were prepared by the phase inversion process using the casting solutions composed of aromatic polyimide (PI-2080), NMP and LiCl. Then the effects of LiCl were studied. The membranes were tested with a flow type apparatus using 0.3% aqueous solutions of poly (ethylene glycol). The addition of LiCl to the casting solution was very effective for the preparation of polyimide UF membranes with molecular weight cut-off characteristics between 20000 and 100000. The membranes made from the casting solution composed of over 2 wt% LiCl could be used for the supporting membrane of a composite.View full abstractDownload PDF (1196K) -
Hiroshi YANAGISHITA, Takashi NAKANE, Hiroshi YOSHITOME1992 Volume 49 Issue 12 Pages 1015-1023
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPreparation of a solvent-resistant membrane has been investigated to develop ultrafiltration and reverse osmosis membranes for organic solutions. Asymmetric membranes were prepared by the phase inversion process from casting solutions composed of aromatic polyimide (PI-2080), solvent and additives. The membrane were tested with a flow-type apparatus using 0.3% aqueous or organic solutions of poly (ethylene glycol) (PEG MW=200-100000). The membranes were made from the casting solution composed of 25wt% polyimide, 25wt% NMP, and 50wt% dioxane by the use of acetone as the gelating solution. They exhibited a rejection of 95% with a toluene flux of 0.12 m3/m2·D for 0.3% PEG400 toluene solution at 40kg/cm2.View full abstractDownload PDF (2501K) -
Isamu UEMURA, Kiyoshi IKEDA1992 Volume 49 Issue 12 Pages 1025-1027
Published: December 25, 1992
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSAbrasion resistance values of thermoplastic polyurethane were investigated. The method of testing employed abrasives. Two samples of polyurethane, prepared from polycaprolactone, 1, 4-butanediol and 4, 4′-diphenylmethane diisocyanate, were tested. The sample that had lower hardness and lower dynamic modulus showed higher abrasion resistance than the other. When the temperature was raised, the abrasion resistance value was improved. Samples compressed by a steel ball showed different compression marks. The results showed that the lower dynamic modulus sample had larger contact area with abrasive and that the abrasive containing layer had improved the abrasion resistance.View full abstractDownload PDF (1033K)
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