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Volume 59, Issue 5
Displaying 1-4 of 4 articles from this issue
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Takahiro SEKI2002 Volume 59 Issue 5 Pages 253-266
Published: May 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPrecise manipulations of flexible polymer materials at nanometer levels essentially rely on the interfacial and supramolecular organizations. This review article summarizes research topics on the organization and dynamic manipulation of two classes of photofunctional polymers, i. e., photochoromic polymers and polysilanes (Si-catenated polymers). The former part introduces dynamic photomechanical effects of photochromic polymers in organized states (mostly monolayer systems) and the surface relief gratings formed via photoinduced mass transfer. The latter part summarizes new research trends regarding supramolecular manipulations of polysilanes. It is also shown that various types of surface monolayers strongly affect the state of polysilane chains. The controlled organization of the above soft photofunctional polymers and their dynamic controls should be of essence to advance the polymer nano-technology and creation of new classes of smart systems.View full abstractDownload PDF (5581K) -
Mitsuhiro FUKUDA, Hiroaki KIKUCHI2002 Volume 59 Issue 5 Pages 267-273
Published: May 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe free space in melt, rubbery, and glassy cis-polyisoprene (cis-PI) has been investigated by inserting hypothetical sphere molecules of various sizes. The polymer structures at various temperatures were created by molecular dynamic simulations. The accessible volume was calculated by counting the subcells in which hypothetical sphere from σ=3.0A to 6.0A (σ means the atom size in Lennard-Jones (12, 6) potential) can be successfully inserted into the systems. The accessible volume is randomly located for the various sizes of the clusters in the system. The number of the clusters and the volume fraction of the clusters with the particular size were analyzed. In low ternperature rubber (273 K), the accessible volumes seemed to be isotropically shrunk when compared with the volumes in the melt state (373 K). In contrast, at glassy state (173 K) some of the accessible volumes which accommodate the spheres from σ=3.0A to 5.0A in rubbery state are frozen near the glass transition (273 K), resulting in the existence of the unrelaxed volume.View full abstractDownload PDF (2106K) -
Daisuke SAWAI, Kazuto HATAKEYAMA, Tetsuo KANAMOTO2002 Volume 59 Issue 5 Pages 274-280
Published: May 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA two-stage draw technique, consisting of the initial solid-state coextrusion followed by the second-stage tensile drawing, was applied. for ultradrawing ofthree acrylic polymers with different thermal stabilities, i. e., poly (acrylonitrile) (PAN) and two copolymers of acrylonitrile with methyl methacrylate (AN/MA) or methacrylic acid (AN/MAA). Although optimum draw temperatures for the second-stage draw were 170-180°C for all of the three polymers, the maximum achieved total draw ratios (DRt) were-70 for PAN and AN/MA and-45 for thermally less stable AN/MAA. Thus, the highest achieved chain orientation function fc=0.988 for AN/MAA was significantly lower than fc=0.995 for the other two polymers. It is noted, however, that the fc value achieved for AN/MAA was significantly higher than the highest fc value of-0.97 previously reported for tensile drawing of a PAN fiber. These facts indicate that the two-stage draw technique is an excellent technique for achieving higher draw and chain orientation. The highest tensile modulus and strength were obtained by drawing of AN/MA; the values were 24 and 1.3 GPa, respectively.View full abstractDownload PDF (1659K) -
Noriko KUWAHARA, Hisashige KANBARA, Akihiko DOBASHI2002 Volume 59 Issue 5 Pages 281-286
Published: May 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSUV-curable crystalline polymer was synthesized and investigated. The polymer has high fluidity before UV irradiation and it was curable by irradiation while retaining its amorphous state. Although the side chain crystalline polymer was fluid and transparent above the melting point, it was less fluid and opaque below it. The phase transition was reversible. The polymer was found to be less fluid and transparent after irradiation above the melting point.View full abstractDownload PDF (1434K)
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