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Volume 55, Issue 6
Displaying 1-10 of 10 articles from this issue
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Yoshiharu Miyashita, Yoshiyuki Nishio, Tadashi Akamatsu, Noritaka Kimu ...1999 Volume 55 Issue 6 Pages 254-260
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSCollagen/poly (vinyl alcohol) (PVA) and chitosan/PVA blends were cast into films from mixed polymer solutions in aqueous acetic acid. Transition behavior of two series of binary blends was examined by DSC measurements. Composition-dependent shift in the glass transition temperature (Tg) of PVA was observed for chitosan/PVA blends and the melting point of PVA was depressed systematically with increasing chitosan content. On the other hand, the less significant shift in Tg of PVA was observed for collagen/PVA blends. These results suggest that the chitosan is compatible with PVA, while collagen is incompatible with PVA. An attempt was made to introduce crosslinks into both series of blends with the aid of glutaraldehyde. Enhancement of the compatibility was achieved for collagen/PVA blends and the mixing state was improved by the introduction of the crosslinking in consequence of the bridge formation between PVA and collagen molecules. On the other hand, chitosan/PVA blends lost their high compatibility due to the preferential crosslinking among chitosan chains. Elongation/contraction behavior of the crosslinked collagen/PVA blends during the alternate immersion in water and concentrated LiCl solution was examined. Further, the moduli of crosslinked collagen/PVA and chitosan/PVA blend hydrogels were also discussed in terms of the degree of crosslinking and the higher order structure of collagen in the hydrogel.View full abstractDownload PDF (578K) -
Hideki Yamane, Aya Inoue, Mitsuko Koike, Masaoki Takahashi, Keiji Igak ...1999 Volume 55 Issue 6 Pages 261-266
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSTranilast, N- (3, 4-dimethoxycinnamoyl) anthranilic acid), which suppresses the fibro blast hyperpalsia, and poly (ε-caprolactone) (PCL), a biodegradable polyester with a low melting point, were blended and melt spun to produce the drug releasing biodegradable fibers.
Thermal analyses, polarized optical microscope observation, and WAXD analyses revealed that tranilast existed as crystal in PCL solid at room temperature and dissolved in molten PCL at an elevated temperature. This tranilast acted either as a crystal nucleating agent or an impurity which obstracted the crystallization of PCL depending on the tranilast content and the thermal history.
Melt-spun fibers of PCL/tranilast blends had mechanical properties which deteriorated with increasing tranilast contents. The drug release rate decreased with increasing draw ratio. This seems to be attributable to high crystallinity of drawn fibers.View full abstractDownload PDF (1837K) -
Tomoya Yamatani, Shigeru Tasaka, Norihiro Inagaki1999 Volume 55 Issue 6 Pages 267-273
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSMelecular weight of polymer surfaces (polystylene, polyethylenetelephthalate, polyvinylchloride and ethylene/vinylacetate copolymer (75/25)) treated with low temperature Ar plasma (direct, remote and plasma-graft treatments) was measured by gel permeation chromatography. To put the information of the polymer surface, thin films with about 500nm thick were employed for the measuremet. Plasma-graft polymerization using methylmethacrylate was performed after Ar plasma exposure to the films. The molecular weight depression of the polymers may proceed from the chain ends of polymers by plasma. It is found that the damaged layer depth of these polymers by ions or radicals from plasma is less than 10nm, and the effect of the UV is to reach to the samples deepen. Therefore, the polymers plasma-treated can be divided into two types ofcrosskining mainly by the UV and decomposing mainly by ions or radicals. Plasma-graft polymerization is effective for the polymers of the closslinking type by plasma and for the polymers of disintegrated type in the condition without the deposition of the low molecular compound reduced.View full abstractDownload PDF (1993K) -
Osamu Ihata, Takashi Kato1999 Volume 55 Issue 6 Pages 274-278
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSSupramolecular liquid-crystalline polyamide complexes were obtained by the formation of double hydrogen bonding between a 2, 6-bis (acylamino) pyridyl moiety in the backbone of a polyamide and 4-alkyloxybenzoic acid derivatives. These polymeric complexes behaved as single components of liquid-crystalline polymers and exhibited stable and enantiotropic mesophases when benzoic acid derivatives had substituents such as methoxy, methyl, chloro, and nitro groups at 3-position. Supramolecular copolymeric structures were also formed by complexing the polyamide with two kinds of 4-alkyloxybenzoic acids.View full abstractDownload PDF (990K) -
Isao Ikeda, Eriko Yamaoka, Yasushi Maeda1999 Volume 55 Issue 6 Pages 279-282
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSCellulose acetate azo-initiator (CAI) was prepared by treating celluose acetate (CAc) with 4, 4'-azobis (4-cyanovaleric acid) (ACVA) in pyridine under the existence of p-toluenesufonyl chloride (TsCI). The degree of substitution (DS) by azo group leveled off with TsCI concentration over 1mol/L and with ACVA concentration over 0.1mol/L for CAc concentration of 0.38mol/L. The reaction was completed within 30min. Vinyl monomers such as styrene (ST) and methyl methacrylate (MMA) were easily polymerized by CAI to prepare the graft copolymers. The rate of polymerization and grafting of MMA were larger than those of ST. Increase in DS by azo group led to incresse in conversion and grafting of monomers. Grafting efficiency of monomers and apparent initiator efficiency (ATE) were 40_??_50% and 0.7_??_1.9%, respectively.View full abstractDownload PDF (251K) -
NOBUYUKI FUKUNAGA1999 Volume 55 Issue 6 Pages P188-P192
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
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TAKAHISA KANDA, MASAHIRO SAMEJIMA1999 Volume 55 Issue 6 Pages P193-P197
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
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YUKIHIRO MAEKAWA1999 Volume 55 Issue 6 Pages P198-P200
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
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TOSHIFUMI SUGAI1999 Volume 55 Issue 6 Pages P201-P204
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
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TERUO OUCHI1999 Volume 55 Issue 6 Pages P205-P208
Published: June 10, 1999
Released on J-STAGE: November 28, 2008
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