All issues
Predecessor
Volume 44, Issue 12
Displaying 1-9 of 9 articles from this issue
- |<
- <
- 1
- >
- >|
-
Nobuyoshi SASAKI, Tetsuo YOKOYAMA1987 Volume 44 Issue 12 Pages 857-865
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSCrosslinked polyurethane ionenes with different lengths of ionene segments were prepared by using poly (oxy-tetramethylene) glycol (Mn=984 and 2040) and 4, 4′-diphenylmethane diisocyanate as starting materials. The morphology and mechanical properties were studied. The equimolar reaction of the isocyanate-terminated prepolymer with 2-dimethylaminoethanol in DMF yielded a multifunctional amino-terminated prepolymer containing isocyanurate groups as branching points. Therefore, the crosslinked polyurethane ionenes were obtained by the reaction of the aminoterminated prepolymers with dihalides: p-xylylenedichloride (XDC) and 1, 6-dibromohexane (DBH). The ionene segment length was varied by adding N, N, N′, N′-tetramethylhexanediamine. With the increase of ionene segment length, the spherulites consisting of ionene were observed more distinctly in SEM micrographs. These polyurethane ionenes showed high 100% moduli (3.6-15.7MPa) and high tensile strengths (37.7-63.4MPa). DBH series of polyurethane ionenes showed diffraction peaks due to ionene segments in their X-ray diffraction curves, whereas XDC series of polyurethane ionenes showed amorphous halos. The differences in the results were explained by the formation of ionene segments with different lengths; that is, in DBH series the ionene segments with longer segment lengths were formed owing to its good solubility in DMF, while in XDC series the ionene segments with shorter lengths were formed.View full abstractDownload PDF (2124K) -
Nobuyoshi SASAKI, Tetsuo YOKOYAMA1987 Volume 44 Issue 12 Pages 867-876
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe phase separated structures of crosslinked polyurethane ionenes with different lengths of ionene segments were studied. The contributions of ionic bonds in the concentration of effective network chains, νc/V, which were estimated from stress-strain measurements, were separated from those of covalent bonds. The ionene segment consists of N, N, N′, N′-tetramethylhexanediamine and 1, 6-dibromohexane (DBH series) or p-xylylenedichloride (XDC series). Small angle X-ray scattering patterns showed the existence of a superstructure with a long period; this results suggests that the polyurethane ionenes have hard ionene domains. The ionic bonds greatly contributed to the total νc/V. As the ionene segment length increased, the primary νc/V due to ionic bond decreased but the secondary νc/V markedly increased. A relation between the primary νc/V and the degree of phase separation estimated from dynamic mechanical measurements was noticed. As the degree of phase separation increased, the primary νc/V decreased in DBH series and increased in XDC series. These different trends in the primary νc/V arise from the different sizes of ionic domains in the two series of polyurethane ionenes.View full abstractDownload PDF (1498K) -
Kimihiro ADACHI, Muneaki YAMAGUCHI, Takako TAKAHASHI, Katsutoshi TANAK ...1987 Volume 44 Issue 12 Pages 877-884
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe affinity between glass flakes (GF) treated with silane, titanate, and phosphate coupling agents (SCA, TCA, and PCA) and epoxy resin cured with hexahydrophthalic anhydride and 4, 4′-diaminodiphenylmethane was studied by dynamic modulus, compressive strength, and SEM measurements. The volume fractions of GF in the composite materials were 0.49-0.61. SEM photographs of cut edgewise surfaces of the filled samples show that GF particles untreated and treated with coupling agents are aligned as a layer. Dynamic mechanical properties of the specimens were measured over the temperature range from room temperature to about 250°C. The composite materials showing large relative moduli (Ec′/Em′), especially in the rubbery region (T=Tg+50°C), have strong affinities between GF and epoxy resin. The composite materials filled with GF treated with SCAs, whose large exothermic peaks are found by DSC measurement, have larger compressive strengths than those treated with TCAs and PCAs. The Ec′/Em′ values at rubbery region have a linear relationship to the ratios of compressive strength (σc/σm). Therefore, use of the Ec′/Em′ values near the rubbery temperature is appropriate to evaluate the affinity.View full abstractDownload PDF (2398K) -
Fumio HOSOI, Kenji SAITO, Keizou MAKUUCHI, Masumi KOISHI1987 Volume 44 Issue 12 Pages 885-891
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolymer-coated spheres, obtained by the graft polymerization of methyl methacrylate (MMA) onto porous spheres based on cellulose by the pre-irradiation method, were used as matrices for the drug sustained release system for salicylic acid. The adsorption of salicylic acid was carried out by dipping the grafted spheres in a 50% aqueous ethanol solution containing salicylic acid. The amount of salicylic acid adsorbed (Q) increased proportionately with the percent graft of MMA (G) to the power of 2.9. Adsorption mechanism of salicylic acid could be expressed in term of Langmuir's adsorption isotherm. The ratio of constants for adsorption and desorption (k) and the saturated amount of salicylic acid adsorbed (Q0) were expressed as k=k1G and Q0=k2G2.4, respectively. These results indicate that the number of adsorption sites increased proportionately with the nth power of G as a results of the interaction of grafted poly (methyl methacrylate) (PMMA) and cellulose. Similar results were obtained with grafting of MMA, MMA-styrene (St), and MMA-methacrylic acid (MAc) in the presence of salicylic acid.View full abstractDownload PDF (1263K) -
Toshisada TAKAHASHI, Hidefumi NAGATA1987 Volume 44 Issue 12 Pages 893-896
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe solid-state morphology of poly (hexamethylene p. p′-bibnzoate) (BB-6) and its dependence on the liquidcrystalline texture was studied by transmission electron microscopy. Thin films of BB-6 were prepared by casting a solution of the polymer in tetrabromoethane onto mica at 150°C. The temperature of the thin film was controlled on a hot-plate. The thin, liquid-crystalline films (210°C) which formed from the isotropic melt (260°C) were cooled gradually to room temperature. Long, plate-like structures composed of stacked lamellar crystals were formed in a thin film prepared from the thermotropic melt. Some of the long plates branched off or sometimes coalesced with neighboring ones to form a higher order, supermolecular structure. Spherulitic structures developed by the concentrical arrangement of lamellar crystals were also observed. These structures were taken to be derived from a smectic texture noted in the liquid-crystalline state of BB-6. An attempt was made to explain such a morphology in terms fo Dupan's cyclide by assuming that a hyperbola in the cyclide is parallel to the surface of the BB-6 film.View full abstractDownload PDF (1754K) -
Masaharu ASANO, Masaru YOSHIDA, Isao KAETSU, Yasushi MORITA, Hironobu ...1987 Volume 44 Issue 12 Pages 897-903
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe polymerization rate of β-propiolactone (PL) by irradiation at -78°C in vacuo increased markedly with the irradiation dose of up to 50kGy and then gradually increased at an irradiation dose of up to 200kGy. The yields of poly (PL) obtained at irradiation doses of 50 and 200kGy were 22 and 25%, respectively. The polymer was shaped into a cylindrical form with high rigidity and density by pressing at 200 kg/cm2 in a range of 50°C to 75°C. The in Vivo degradation of cylindrical specimens was checked by implanting subcutaneously in the back of male Wistar rats. The degrees of in Vivo degradation of poly (PL) obtained at 5, 10, 50, 100, 160, and 200kGy irradiations were 5, 9, 25, 34, 37, and 40%, respectively. The viscosity (ηsp/c value) of these polymers showed a decrease tendency with an increase in the irradiation dose. From the relationship between the ηsp/c value and the in Vivo degradation, it was found that the degree of in Vivo degradation had a inflection point at a η>sp/c value of 0.4 dl/g (30kGy irradiation). That is, the in Vivo degradation of poly (PL) with η>sp/c values below 0.4 dl/g (above 30kGy irradiation) was markedly accelerated by a slight decrease of viscosity, but such an acceleration was not remarkable at η>sp/c values aboves 0.4 dl/g (below 30kGy irradiation). This may be primarily attributed to the scission of polymer chains during the irradiation polymerization. The data of X-ray diffraction patterns and DSC curves also showed that the in Vivo degradation is influenced by a change in the crystallinity or by a decrease in the melting point of poly (PL).View full abstractDownload PDF (1433K) -
Koichi TAKADA, Hidehiko MATSUYA, Hiroshi KISHIKI1987 Volume 44 Issue 12 Pages 905-910
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSUV degradation of poly [1- (trimethylsilyl) -1-propyne] donated as PMSP and effects of sensitizers on the degradation were studied. PMSP was degradated by UV irradiation under air and in vacuo. The rate of degradation was enhanced in a presence of oxygen. The degradation was random chain scission as found from the relationship between the applied dose and the reciprocal of molecular weight of PMSP degraded. PMSP polymerized by NbCl5 turned out to be more degradable than that polymerized by TaCl5. This result is due to the difference of geometric structure of PMSP. The effective sensitizers chosen by a screening test were quinones such as 2-ethylanthraquinone which could abstract hydrogen from PMSP. In the spectral sensitization by the use of i line (365nm) and g line (435 nm), the composite sensitizers of quinone compound coupled with other compounds were effective. The energy transfer between composite sensitizers plays a role in the sensitization.View full abstractDownload PDF (937K) -
Koichi TAKADA, Hidehiko MATSUYA, Hiroshi KISHIKI1987 Volume 44 Issue 12 Pages 911-916
Published: December 25, 1987
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPhotoresist characteristics of the sensitized poly [1- (trimethylsilyl) -1-propyne] donated as PMSP were extensively evaluated. PMSP sensitized by 2-ethylanthraquinone became a positive working photoresist having a sensitivity of 100 mJ/cm2. The sensitivity, resolution and linewidth dimensionality depend on the developers employed. When ketone compounds were used as a developer, linewidth dimensionality after developing reached a practical level. Addition of nonionic surfactant to the resist enhanced the sensitivity. Likewise, heat treatment, so-called interbake, resulted in the enhancement of both sensitivity and resolution. As for resistance for O2RIE, PMSP carries enough durability to be compared with that of the novolak resin used as the bottom layer in the bilayer photoresist. But linewidth dimensionality patterned after O2RIE was insufficient for the practical requirements, because of the shrinkage of patterns during O2RIE. Shrinkage of the pattern during ion ething seems to be an intrinsic defect in the system of bilayer PMSP photoresist.View full abstractDownload PDF (1284K) -
Kazuko HAYASHI, Hiroshi FUKUMURA, Susumu YOSHIKAWA, Noboru YAMAMOTO, T ...1987 Volume 44 Issue 12 Pages 917-924
Published: December 25, 1987
Released on J-STAGE: March 25, 2010
JOURNAL FREE ACCESSTo examine the influence of radiation-induced oxidation on the antithrombogenicity of polymers, polytetrafluoroethylene (PTFE) and low density polyethylene (PE) tubes were irradiated with gamma-ray and then treated with water at 50°C, and surface characterization and evaluation of their antithrombogenicity were done. Irradiation was carried out mainly in argon with 0.14-0.47 MR for PTFE and in air or water with 0.44-8 MR for PE. Data of ESCA and zeta-potential showed the introduction of oxygen-containing groups onto the irradiated surfaces (ca. 10 mol% for the irradiated PE), and the contact angle of water for the PTFE and PE surfaces decreased to 98°and 80°, respectively. The relative patent time in canine peripheral veins reduced markedly with dose. No activation of complement and contact phase were, however, observed for all specimens in vitro, while platelet adhesion was found to increase for the irradiated specimens in vivo. Consequently, the reduction in the antithrombogenicity of the irradiated surfaces is mainly due to the enhancement of platelet activation resulting from a decrease in hydrophobicity of the surfaces.View full abstractDownload PDF (1712K)
- |<
- <
- 1
- >
- >|