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Predecessor
Volume 48, Issue 11
Displaying 1-10 of 10 articles from this issue
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Akira KAITO, Kazuo NAKAYAMA1991 Volume 48 Issue 11 Pages 663-670
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSCrystalline and amorphous sheets of poly (ether ether ketone) (PEEK) were stretched using rolling and roller-drawing techniques. The mechanical properties and the molecular orientation in the stretched sheets were studied by tensile tests, wide angle X-ray diffraction (WAXD), and birefringence. In the case of crystalline PEEK sheets, the Young's modulus and the tensile strength increase with increasing draw ratio; the Young's modulus reaches 9.9 GPa at the highest draw ratio. The crystal c-axis and amorphous molecular chains orient in the draw direction, and the (100) plane is aligned in the sheet plane of the rolled and roller-drawn sheets. In the roller-drawing experiments of amorphous PEEK sheets, the draw ratio is confined to a range of 2.8-3.1 and is not sensitive to processing conditions. Stress-induced crystallization takes place in the roller-drawing process of amorphous PEEK sheets. The degree of crystallinity and birefringence increase with increasing draw velocity.View full abstractDownload PDF (1324K) -
Kunisuke SAKAMOTO1991 Volume 48 Issue 11 Pages 671-678
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSThe biaxially oriented PET films manufactured by a tenter are anisotropic in the optical properties. Their physical as well as optical properties depend on each position of the films. Biaxially oriented commercial PET films were used to determine the birefringene, planar orientation and direction of the primary refractive index and to characterize the distinctive features of the films. The birefringence at the film edge was larger than that at the film center. The birefringence patterns (birefringence-transverse position of a film) were downward convex and had a minimum near the center of the films. Zero birefringence existed near the center of film only for the films prepared under the completely balanced condition. In this case, the birefringence increased in proporton to the distance from the center to the edge. On the other hand, the planar orientation was uniform at every place on the films. Such optically anisotropic properties were explained theoretically, based on the assumption that a refractive index ellipsoid changed in proportion to the draw ratio.View full abstractDownload PDF (1308K) -
Kazuo NAKAYAMA, Akira KAITO1991 Volume 48 Issue 11 Pages 679-684
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSThe rolling of commercial extruded sheets of polyoxymethylene (POM) was carried out at the roll temperature of 150°C. The action of a tensile force was applied to the product during the hot rolling. A stable rolling process has been conducted experimentally. The relationships between mechanical properties and rolling conditions were studied. The tensile force applied to the product affected both the rolling force and the rolling ratio. The main effect of increasing the rolling ratio was to increase the tensile modulus and the strength of the rolled sheet. A striking feature of specimens obtained at high rolling ratio is their high degree of transparency.View full abstractDownload PDF (944K) -
Akeharu TSURUTA, Tadashi USUKI, Shinji TANAKA1991 Volume 48 Issue 11 Pages 685-690
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSThe stress-strain behavior and morphological changes on drawing at room temperature have been investigated for the three types of poly (phenylene sulfide) (PPS) films with different spherulite sizes. The spherulite sizes were controlled by melting at different temperatures and crystallization at a constant temperature of 240°C. Annealed samples prepared from a melt-quenched film were also investigated. Each type of PPS films with different crystallinities was prepared by changing either the crystallization time or the annealing temperature. In quenched/annealed samples (Type III) where a spherulitic texture was not developed, the draw stress increases steadily, and the elongation at break decreases rapidly with increasing crystallinity. On the other hand, the draw stress for the melt-crystallized spherulitic samples (Types I and II) is nearly constant regardless of the crystallinity until about 20%, and the drawability for these samples was remarkably higher than for the Type III samples. These tendencies are more prominent for the films with larger spherulitic sizes than for the films with smaller ones. The drawn films showed drastic morphological changes in the interspherulitic regions and the increase in orientation of amorphous chains. These facts, combined with the dynamic mechanical measurements which show the difference in amorphous chains mobility for each type of PPS films, strongly suggest that the drawability of PPS films at room temperature is highly influenced by the restrictions imposed on the chain mobility of amorphous regions.View full abstractDownload PDF (1758K) -
Shuji MATSUZAWA, Liande SUN, Kazuo YAMAURA1991 Volume 48 Issue 11 Pages 691-697
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSSyndiotacticity-rich poly (vinyl alcohol) s (s-PVA) of high degrees of polymerization (DP=7900, 12600) were prepared from poly (vinyl trifluoroacetate) s obtained by bulk-polymerization at 40° with 2, 2'-azobis (2, 4-dimethylvaleronitrile) as the initiator. Gel filaments of the s-PVAs were prepared by extruding into cold methanol (-20°) the solution in water-dimethyl sulfoxide (20: 80, volume ratio) (polymer concentration, 3.5 g/dl; diameter of a nozzle, 0.8 mm). The maximum draw ratio of the filaments was about 14 at 230°. The fibers, obtained by drawning 12 times the gel filaments of s-PVA with DP=7900, showed the highest tensile modulus of 30 GPa, strength at break of 1.9 GPa, crystallinity of 70%, and birefringence of 5.0×10-2. Crystallinity up to 30% is considered to interfere with high drawing of the gel filaments. The fibers prepared from the gel filaments of commercial atactic PVA with DP=17900 under the same conditions and elongated 13 times at 220° showed Young's modulus and the tensile strength of 18 GPa and 1.3 GPa, respectively.View full abstractDownload PDF (1344K) -
Tsutomu NAKAMURA, Masachika YOSHINO1991 Volume 48 Issue 11 Pages 699-702
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSRecently many molding vendors have adopted injection-molding machines equipped with automatic and high cyclic curing mold system for silicone. It is very important for the molding of silicone rubber to examine its flowing properties on curing mold. This paper presents correlations between the flowing properties of silicone rubber which is crosslinking and is flowing in a spiral mold, and the physical properties of this flowing rubber. The increase in pressure of injection-molded rubber was measured by a pressure sensor on spiral mold, the results were associated with the crosslinking process.View full abstractDownload PDF (597K) -
Toshio KUNUGI, Akihiro SUZUKI, Tetsuya TSUIKI1991 Volume 48 Issue 11 Pages 703-710
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSIn order to improve the mechanical properties of the zone-drawn poly (ethylene terephthalate) (PET) fiber, the fiber was annealed under an extremely high tension, which was 95% of the tensile strength at break. The annealing was carried out at 100°C to orient the chain segments with longer relaxation times. The fiber zone-drawn 3 times, ZD-3 fiber, has a draw ratio of 7.2 times and a birefringence of 0.250. The fiber annealed subsequently under high tension, H fiber, has values of 7.5 times and 0.279. The birefringence of H fiber exceeds the intrinsic value (0.251) already reported. Crystallinity and orientation factor of crystallites for the ZD-3 fiber are almost the same as those for the H fiber. These fibers have a cyrstallinity of ca. 58% and the orientation factor of crystallites is near unity. On the other hand, the orientation factor of amorphous phase for the ZD-3 fiber is a value of 0.646, and that for the H fiber increases up to 0.854. The H fiber obtained has a Young's modulus of 30 GPa and a tensile strength of 1.7 GPa. High modulus and high strength PET fiber was prepared by using the annealing under an extremely high tension.View full abstractDownload PDF (1399K) -
Kiyoichi MATSUMOTO, Hiroyuki SAITOH1991 Volume 48 Issue 11 Pages 711-717
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSIt is not always easy to keep moisture away during film formation from dope of polyamic acids. Two kinds of Kapton and Upilex-S types of polyimide were made from dope of polyamic acid; the rates of hydrolysis caused by micro-moisture in these dopes were determined. The relationships for dopes with no water or 1 vol% water were well fitted by an Arrhenius type equation: log [(1/P) - (1/P0)] t-n=(A/T+B). So the apparent activation energy of hydrolysis for no water or 1 vol% water in the two types of dope of polyamic acid is 16-17 kcal/mol on non-water and 18-20 kcal/mol on 1 vol% water content. The concentrated dope from which the film were prepared showed Bingham's flow. The viscosity which dopes included no or 1 vol% water was increased with increasing degree of polymerization of polyamic acid.View full abstractDownload PDF (1111K) -
Seiji UJIIE, Kazuyoshi IIMURA1991 Volume 48 Issue 11 Pages 719-724
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSThe ionic liquid-crystalline polyethylenimines (LCPEIs) with ammonium ion moieties, the ion-complex-type liquid-crystalline polymer (ICLCP) and their low-mass model liquid crystals (LMLCs) were all synthesized. Their thermal properties and orientational behavior were studied. LCPEIs were prepared from polyethylenimine with the bromoalkyl mesogenic compound. ICLCP was obtained by ion exchange reaction between the polyanion and the cationic low-mass liquid-crystal. LCPEIs, ICLCP, and LMLCs exhibited enantiotropically thermotropic smectic phases. Ammonium ion moieties enhanced the thermal stability of the smectic phase, and were effective to form spontaneously the homeotropic structure in the smectic phase. The formed homeotropic structures of ionic liquid-crystalline polymers remained unaltered on cooling below the glass transition temperature. The smectic layer structures were studied by X-ray diffraction measurement and conoscopic observation. In the smectic layers of LCPEIs, ICLCP, and LMLCs, the neighboring mesogenic groups overlapped with each other, and the ammonium ion moieties independently aggregated to form a sublayer.View full abstractDownload PDF (2137K) -
Keiko ITO, Masami INOUE, Masaharu MORIYASU1991 Volume 48 Issue 11 Pages 725-735
Published: November 25, 1991
Released on J-STAGE: November 22, 2010
JOURNAL FREE ACCESSThe photoablating behavior of various polymers (polyimide, tetrafluoroetylene-hexafluoropropylene copolymer, poly (methyl methacrylate), polytetrafluoroethylene, polypropyrene) irradiated by 193nm, 248nm, and 351nm excimer lasers and 266nm, 532nm, and 1064nm YAG lasers has been studied. The conditions for producing sharp and low-damage pattern, the etched depth, and the threshold laser energy density for ablation with various polymers and lasers are discussed. These experiments reveal that a low-damage pattern is obtained with high absorption coefficient (about 104 cm-1) and that low absorption causes the thermal damage with even ArF (193nm) laser. It is considered that the ablating characteristics depend on the etching unit per pulse, which is connected with the laser absorption. Moreover, it is recognized that the energy given by threshold laser energy density correlates well with the energy needed for raising to the volatile temperature on each polymer.View full abstractDownload PDF (2172K)
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