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Predecessor
Volume 59, Issue 1
Displaying 1-11 of 11 articles from this issue
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Shizue HAYASHI2002 Volume 59 Issue 1 Pages 1-7
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe synthesis of several novel cellulose carbonate derivatives and their physical properties are reported. Disubstituted cellulose carbonate derivatives were synthesized by transesterification with triacetylcellulose (CTA) and diphenyl carbonate (DPC). Only C3 and C6 acetyl groups on the pyranose ring could be replaced with phenyl carbonate groups. An insoluble product was obtained from the mixture of cellulose and diphenyl carbonate. In contrast, trisubstituted derivatives were formed for the first time in the reaction of unmodified cellulose and phenyl chloroformate in dimethylacetamide-LiCl solution. These trisubstituted cellulose carbonate derivatives had high solubility in organic solvents, excellent elastic properties, and good thermoplasticity for processing.View full abstractDownload PDF (1331K) -
Isamu KANEDA, Toshio YANAKI2002 Volume 59 Issue 1 Pages 8-14
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe heat-induced gel-forming nature of succinoglycan was studied by rheology and dynamic light scattering. A succinoglycan sample with weight-average molecular weight 3.5×105, prepared from native succinoglycan by sonication, was investigated. The viscosity of the polysaccharide solution distinctly increased above the overlap-concentration, 2 mg/mL, after heat treatment. The dynamic modulus of the polysaccharide solutions was measured in intact and heat-treated status. The heat-treated sample whose concentration was above 10 mg/mL showed a weak-gel like nature. Moreover, it has become clear by dynamic light scattering that the weal-gel consisted of micro-gel that is 500 nm in diameter. We have concluded that the nature of heat induced gel-forming is due to re-association of the double-helical structure in the succinoglycan.View full abstractDownload PDF (1516K) -
Preparation and Physical Properties of 2-Vinylpyridinium silicate-styrene-butadiene RubberSatoshi NAKAKITA, MING Zhang, Shin-ichi INOUE, Hiroshi OKAMOTO2002 Volume 59 Issue 1 Pages 15-20
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESS2-Vinylpyridinium silicate-styrene-butadiene rubber (Si-PSBR) was prepared from 2-vinylpyridine-styrene-butadiene rubber (PSBR) latex and silicic acid generated from water glass. In stress-strain behavior of Si-PSBR, although the remarkable telescopic motion as an elastomer was not obtained, the maximum stress increased about 2.5 times as compared with unmodified PSBR. In the vulcanizates of Si-PSBR, the compression set decreased about 5% because of crosslink of silicic acid with the siloxane bond.View full abstractDownload PDF (1856K) -
Takashi IIZAWA, Takashi FUJIMOTO, Eiji MIYATA, Fumihiko MATSUDA2002 Volume 59 Issue 1 Pages 21-28
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSCylindrical poly (t-butyl methacrylate) gels (GBM) and GBM with a small amount of methacrylic acid unit were prepared. When GBM with p-toluenesulfonic acid as an acid catalyst was placed in a heated alkyl acetate, which works as an acid acceptor, it started to swell from the outer surface and to deesterify at the same time. At the end of the reaction, the gel was divided into a swollen shell layer, which had been hardly deesterified, and an unswollen core part, which had been deesterified. The final core size was controlled by the diffusion rate of the solvent and deesterification rate. Accordingly, the core size depended on many factors such as acid concentration in GBM, reaction temperature, concentration and bulkiness of acid acceptor. When the gel capsule aged at 120°C for 1 h was used, the aged shell layer served as a permeation barrier for many chemicals including water. This suggests that the gel capsule obtained is useful for a drug carrier.View full abstractDownload PDF (1755K) -
SUSUMU NIKKESHI, Mituyuki KONNO, Kana OHUHASHI, Takao SHIGIHARA, Nobor ...2002 Volume 59 Issue 1 Pages 29-34
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe number of the used poly (ethylene terephthalate) bottles (PET-bottles) for drinks which are collected has been increasing, while only a limited number of them can be reutilized by injection molding process. Here we investigated the thermal stability and recyclability of PET-bottle flakes (Re-PET) to which modified polyhydric phenol agent was added. The properties of the PET resin were evaluated after 3 repeated moldings. For the PET resin containing 0.02 wt% modified polyhydric phenol, the melt flow rate (MFR) increased from 41g/10 min to 52g/10min after 3 injection molding cycles, while the unfilled Re-PET resin control increased to 108g/10min. These results suggest that the Re-PET molecule depolymerized during the injection molding process due to the thermal energy and stress. On the other hand, we found that the modified polyhydric phenol reduced the crystallinity of the Re-PET resin to approximately 20% of that for the Re-PET at a mold surface temperature 40±3 (°C). These findings suggest that the addition of modified polyhydric phenol in Re-PET improved the stability of Re-PET. This implies that modified polyhydric phenol may be an effective method in the recycling process of PET-bottle flakes.View full abstractDownload PDF (1779K) -
Shohei YOSHIDA2002 Volume 59 Issue 1 Pages 35-43
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA dynamic infrared spectrometer was developed by combining a FT-IR spectrometer with a visco-elastometer in order to analyze relaxations of polymers in terms of functional groups. The polarized-infrared spectrum synchronized with vibrations applied to samples by a visco-elastometer could be measured in the temperature range of 26-150°C and in the frequency range of 1-300 Hz. A series of modified-poly (vinyl alcohol) (PVA) samples was analyzed by this instrument. The relaxation of hydroxyl group of acethyl-modified PVA was detected. Thus, the synchronous spectrum (in-phase spectrum) changed with the frequency as well as with the temperature. The relaxations of the principal functional groups in a series of modified-PVA such as butyral-modified PVA and fluoroacetyl-modified PVA were detected. Further, the tendency of the change of the glass transition temperature with the degree of modification was elucidated in terms of the relaxation of the functional groups.View full abstractDownload PDF (1954K) -
Yoshiaki TOMOTAKE, Yoshio MAEDA, Takehiko GOTOH, Shuji SAKOHARA2002 Volume 59 Issue 1 Pages 44-50
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSEffects of the synthesis temperature and the cross-linker concentration on the formation of thermosensitive N-isopropylacrylamide (NIPAM) porous gels which swell or shrink quickly in response to the change in temperature were examined systematically. The swelling and shrinking properties of the porous gels were also examined. Although phase separation occurs by polymerizing NIPAM at the temperatures above the transition temperature of polyNIPAM (about 32°C), with increasing the cross-linker concentration a structure composed of aggregated microgel particles and pores, i. e. the porous gel, was formed. The swelling rate of such a porous gel was extremely large compared with that of a non-porous gel prepared with low concentration of cross-linkers. The swelling rate of gel composed of fully developed porous structure was almost inversely proportional to the square of the characteristic length of the gel in the swollen state. On the other hand, the shrinking of the gel was very fast compared with the swelling, and the gel prepared with a low concentration of cross-linker also shrank very fast, as did a porous gel prepared with a high concentration of cross-linker. The similarity is due to the fact that the gel prepared with a low concentration of cross-linker is also composed of a percolate structure formed by a phase separation, namely a porous structure, in the swollen state of the initial stage of shrinking process.View full abstractDownload PDF (2546K) -
Kazuro KAWAMURA, Shinichiro OZAWA2002 Volume 59 Issue 1 Pages 51-56
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSFiber reinforced plastics (FRP) of which fiber content was 18 vol% were made from unidirectionally and spontaneously stacked aramid fibers (Technora) and phenol-formaldehyde resin (phenol resin) or furfuryl alcohol resin (furan resin). Characterization of two kinds of FRPs was done from a viewpoint of change of bending strength by heat treatment. When phenol resin was heated at a temperature above 500°C, many cracks appeared, but the formation of cracks was controlled in the FRP.The bending strength of FRP was almost two times larger than that of the resins in case of putting load from the direction of minor axis of fiber. In addition, the bending strength of the FRP made from Technora and furan resin was a little larger than that of the FRP from Technora and phenol resin. The experimental data showed that furan resin was more suitable than phenol resin as a matrix. The straight relationship was observed between the bending strength and the weight loss before carbonization. Also, a power law, σ∝ρn, existed between bending strength (σ) and bulk density (ρ).View full abstractDownload PDF (1565K) -
Chifei Wu, Saburo AKIYAMA, Kazue MORI, Yoshio OTANI, Hitoshi EMI2002 Volume 59 Issue 1 Pages 57-59
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSBlends of chlorinated polyethylene (CPE) and tetrakis [methylene-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] methane (A0-60) were prepared from solution casting. Benzene, toluene and p-xylene were each used as solvents. The dynamic mechanical and thermal properties of those blends were investigated. For the solution-blended samples of CPE/AO-60, a novel relaxation appears above the glasstransition temperature of CPE. However, this novel relaxation is very different from that of melt blended CPE/AO-60 in strength and position. Those differences were found to be caused by the number of hydrogen bonds within the AO-60-rich domain.View full abstractDownload PDF (624K) -
Chifei Wu, Saburo AKIYAMA2002 Volume 59 Issue 1 Pages 60-62
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe dynamic mechanical properties of organic hybrids of chlorinated polyethylene (CPE) and tetralcis [methylene-3- (3, 5-di-tert-buty1-4-hydroxyphenyl) propionyloxy] methane (AO-60) were investigated. In the case of polyethylene chlorinated in solution, the addition of a small amount of AO-60 results in the first peak of the loss tangent due to the glass transition of CPE becoming larger than that of pure CPE. In contrast, for polyethylene chlorinated in suspension, the first peak becomes small. This difference was associated with a delicate change in the hydrogen bond between the α-hydrogen of CPE and the hydroxyl groups of AO-60.View full abstractDownload PDF (526K) -
Hiroshi TSUBAKIHARA, Tomoyuki ITOH, Kohtaku HAYASHI2002 Volume 59 Issue 1 Pages 63-67
Published: January 25, 2002
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSAn experimental study of iodine-doped half oxidized polyaniline (EB) films has been carried out. In the case of a low iodine concentration up to 500 mg/100 mL, the iodine oxdized benzene-diamine blocks to form quasi-delocalized polarons within the blocks. The resulting iodine-doped EB, however, was essentially amorphous and the electrical conductivity was too low to detect. At a higher iodine concentration than 1g/100 mL, the quinone-diimine blocks were also oxdized, polarons were delocalized over the whole EB-molecular chain, and a certain crystallization occurred in the chains. As the iodine content increased, the conductivity increased rapidly and satulated.View full abstractDownload PDF (882K)
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