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Volume 47, Issue 5
Displaying 1-14 of 14 articles from this issue
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Yasuhisa TSUKAHARA, Yoshikazu TSURUTA, Kenji KOHNO, Yuya YAMASHITA1990 Volume 47 Issue 5 Pages 361-370
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSSurface active polymeric UV-stabilizers have been prepared by radical copolymerizations of dimethylsiloxane (DMS) macromonomer, and styrene (St) macromonomer with perfluoroalkylethyl acrylate (FA) and 2- (2-hydroxy-2-vinylphenyl) -2H-benzotriazole (2). Monomer 2 was synthesized according to the procedure by Vogl et al. Prepared graft copolymers were poly (2-g-St) (GUS), poly (2-g-DMS-g-St) (GUSD), and poly (2-co-FA-g-St) (GUFS). A random coplymer of poly (2-co-St) (RUS) and 2- (2-hydroxy-2-ethylphenyl) -2H-benzotriazole (1) were also synthesized for comparison. These polymeric UV-stabilizers were characterized and added to PSt to examine their UV-stabilization for PSt. UV-stabilization of these compounds was investigated by measuring IR absorption intensity of carbonyl groups produced by photo-oxidation. Molecular weight and molecular weight distribution changes by photo-degradation were also measured by GPC. It was found that addition of small amounts of the surface active graft copolymers such as GUSD and GUFS provided more effective UV-stabilization to PSt than RUS and GUS due to surface accumulation of the polymeric UV-stabilizers. Furthermore, stabilization of GUFS was more effective than that of GUSD possibly due to the suitable graft copolymer architecture of GUFS and more effective surface activity of the FA component.View full abstractDownload PDF (1634K) -
Teruo HORI, Hideki NAWA, Taizo IGARASHI, Yoshiharu NAKAMURA1990 Volume 47 Issue 5 Pages 371-378
Published: May 25, 1990
Released on J-STAGE: July 27, 2010
JOURNAL FREE ACCESSComposite membranes having different mixing ratios of Nylon 6 (Ny) and poly (ethylene terephthalate) (PET) were prepared by dissolving Ny and PET in hexafluoro-2-propanol (HFIP), casting the obtained solution on a glass plate and evaporating the solvent in the presence and absence of an electric field. The internal structure of the prepared membranes were investigated using DSC, X-ray diffraction method and electron microscopy. In the composite membranes prepared under electric field, both components were oriented parallel (for Ny/PET=10/0-5.5/4.5) or perpendicular (for Ny/PET=5.5/4.5-0/10) to the membrane surface, while in the membranes prepared under nonelectric field the two components formed a random sea/island structure. Such characteristic membrane structures were influenced the permeation behavior of Orange II through the memebranes from an aqueous solution.View full abstractDownload PDF (1886K) -
Shigetaka SHIMADA, Keiichi KASHIMA, Yasuro HORI, Hisatsugu KASHIWABARA1990 Volume 47 Issue 5 Pages 379-385
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSIn order to characterize a molecularly compatible system and a phase-separated system, the electron spin resonance (ESR) line shape of nitroxide radical labels attached to poly (methyl methacrylate) (PMMA) chain ends in blends with poly (ethylene oxide) (PEO) was studied. The line width increased with the spin-label concentration because of electron spin-spin dipole interactions. Dependence of the line shape parameter upon the concentration of the spin-label could be evaluated; from this the local concentration of PMMA chains in the blend with PEO was determined. The blends were molecularly mixed at 100°C, plunged into liquid nitrogen and then annealed at elevated temperature. After the heat-treatments, ESR measurements were carried out at -196°C. Estimation of the local concentration of the PMMA chains as a function of annealing temperature indicated that phase seperation occurs below 60°C and that molecular mixing occurs above 60°C.View full abstractDownload PDF (1731K) -
Atsuhiko YAMANAKA, Atsushi KAJI, Masao MURANO1990 Volume 47 Issue 5 Pages 387-393
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSMolecular motions of polymer chains depend on blending; these motions are different in bulk and in a polymer blend. In this research, the molecular motions of poly (epichlorohydrin) (PECH) were studied by 13CNMR. They show different behavior in bulk from that in polymer blend. Two types of blend films, PECH/PMMA=60/40 (wt%), were prepared from toluene and THF solution; the former is transparent and the latter is an opaque film. From the temperature dependence of line shape, T1 and T2 in PECH, it is found that the blend film shows the same behavior as bulk but at a higher temperature and that the opaque blend film shows behavior intermediate between that of bulk and that of the transparent film. This result shows that the molecular motion of PECH is inhibited by the surrounding PMMA chains and that the decrease in molecular motion depends on the phase structure. T2 is more sensitive to phase structure in polymer blend than T1. So the slow motion described by T2 is influenced by blending more than the fast one described by T1.View full abstractDownload PDF (1080K) -
Atsushi TAKAHARA, Tatsuo TERAYA, Tisato KAJIYAMA1990 Volume 47 Issue 5 Pages 395-402
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe surface structure and surface molecular mobility of diblock copolymers were investigated based on X-ray photoelectron spectroscopy (XPS) and the dynamic Wilhelmy plate technique. The A-B diblock copolymers used in this study contain styrene as A-component, and hydroxy poly (ethylene glycol) methacryrate (HPEGM), methoxy poly (ethylene glycol) methacryrate (MPEGM), hydroxy poly (propylene glycol) methacryrate (HPPGM), or fluoroalkoxymethylstyrene (FAMSt) as B component. The surface chemical composition of the air-solid interface depended very much on the difference in surface free energy between A and B components. The XPS measurement revealed that the air facing surface was enriched with the components of lower surface free energy. The end group of side chain of B components was also one of the important factors to decide the surface chemical composition. Dynamic contact angle measurements revealed that the advancing contact angle was dependent on the components of lower surface free energy, whereas the receding contact angle was influenced by the components of higher surface free energy. A large scale surface structural reorganization upon environmental change was observed for the block copolymer whose overlayer component had a low glass transition temperature.View full abstractDownload PDF (1472K) -
Hiroki KATONO, Atsushi MARUYAMA, Kouhei SANUI, Naoya OGATA, Nobuhiko Y ...1990 Volume 47 Issue 5 Pages 403-408
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe drug release profiles from PEUUs were examined in terms of the interaction between device and drug in the release system. Crystal violet (CV) was used as a model drug, and polyether poly (urethane urea) (PEUU) s with various compositions of hard segments and soft segments of polyethylene oxide (PEO) were used as release devices. CV release from PEUUs having different initial concentrations of CV was carried out to investigate the effect of the interaction on the release profile. Faster releases of CV in an early stage were observed for PEUU loaded with a higher content of CV. Sorption experiment of CV to PEUU showed that CV was sorbed mainly to PEO segments with Freundlich profile, indicating a dual mode absorption of CV to PEUU. Thus, for the device with higher initial CV concentration, most of the CV molecules dispersed in PEUU interacted weakly so that the release occurred smoothly. In contrast, the release of CV was interfered with by the stronger interaction, when PEUU was loaded with a lower concentration of CV, resulted in a slower release rate.View full abstractDownload PDF (952K) -
Gen-ichi NAKAMURA, Takashi INOUE1990 Volume 47 Issue 5 Pages 409-414
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe concept of Neumann's triangle between three liquids was applied to discuss the multi-phase morphology developed by melt-processing of a ternary blend consisting of polymers (A, B, and C) which are immiscible with each other. For a C polymer-rich system, four morphologies were predicted: (a) isolated particles of A and B, (b) particle composed of A and B stuck together, (c) hybrid particle of A encapsulated by B, and (d) hybrid particle of B encapsulated by A; and the morphological variation was shown to depend on the balance between interfacial tensions. To verify the results, we carried out a‘droplet-sandwich’experiment for polycarbonate/poly (butylene terephthalate) /poly (styrene-co-acrylonitrile) system: i. e., small pieces of C polymer were placed between two layers of polymer A and B, and annealed at melt temperature; then after quenching, the cross-section of the‘sandwich’was observed under a microscope. From the value of cos θ in Neumann's triangle thus obtained, one could explain the recent results of Hobbs et al. for phase morphology in melt-processed blends [Polymer, 29, 1598 (1988) ], indicating that the morphology development is mostly governed by the balance between interfacial tensions and that it is well predictable in the framework of Neumann's triangle concept.View full abstractDownload PDF (1689K) -
Toshio NAKASHIMA, Takatoshi KINOSHITA, Akira TAKIZAWA, Yoshiharu TSUJI ...1990 Volume 47 Issue 5 Pages 415-423
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSA-B-A-type block copolymer (MSiM) membranes consisting of poly (γ-methyl L-glutamate) (PMLG, A component) and polydimethylsiloxane (PDMS, B component) have been prepared. Their structure-CO2 permeability relationships have been investigated. Phase separation between α-helical PMLG and PDMS components has occurred in MSiM membranes, at the interface between the two phases, random-coil structure was induced in the PMLG component. As a result, the sorption behavior of CO2 in MSiM membranes can be explained in terms of the additivity between the solubility of CO2 in the three phases in the membranes: two phases of PMLG (α-helix and random-coil domains) and a PDMS phase. In the PMLG rich MSiM membranes, containing greater than 70vol% PMLG component, the solubility and diffusibility of CO2 decreased with increasing random-coil content of PMLG component. On the other hand, with increasing PDMS content, the permeability of MSiM membrane significantly increased, e. g., the CO2 permeability coefficient of MSiM membrane containing 54vol% PMLG became one order larger than those of the PMLG rich MSiM membranes. Further, MSiM membranes containing greater than 70 vol% PMLG component showed relatively high values (3.5-4.4) of oxygen/nitrogen separation factors.View full abstractDownload PDF (1516K) -
Tadashi UYEDA, Kozo MISE, Hisashi ODANI, Hideroh TAKAHASHI1990 Volume 47 Issue 5 Pages 425-431
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe transport and solution behavior of water vapor in polyethylene/polyamide blend sheets, which were obtained by injection molding under different shearing conditions, was studied at 30°C by the weighing method. The morphological structures of the blend sheets of various compositions were observed by scanning electron microscopy. In sheets prepared under extremely high shear rate conditions, the dispersed phases become shaped like fibers which are oriented in the direction of the flow. On the other hand, in sheets prepared with medium shear rate, sphere-like particles of various sizes disperse in the matrix. The solubility of water in the sheets was not affected much by the difference in morphological structure. The solubility coefficient increased with increasing the content of polyamide component. Apparent integral diffusion coefficients for sheets in which the fibrous domains are oriented in the plane sheet are greater than those for sheets having particle type morphological structure, if a comparison is made at the same composition of the blend. This was interpreted as mostly due to an effect of the preferential orientation of polymer chains. A synergistic effect was observed in the relationship between apparent permeability coefficient and composition in the region where polyamide domains disperse in polyethylene matrix. The effect was more pronounced for the samples which are obtained by extremely high shear rate processing.View full abstractDownload PDF (1712K) -
Toshikazu TAKIGAWA, Yukio TOMINAGA, Toshiro MASUDA, Hideroh TAKAHASHI1990 Volume 47 Issue 5 Pages 433-437
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSInterpenetrating polymer networks (IPN's) composed of segmented polyurethane (SPU) and polyacrylamide (PAAm) have been synthesized in order to investigate how the synthesis conditions affect the PAAm fraction in IPN, and to examine the relationship between the PAAm fraction and degree of swelling of IPN in water. Three types of SPU's, differing in the molecular weight of polytetramethyleneglycol forming the soft segments, were used for the IPN preparation. SPU films were immersed in a solvent containing acrylamide monomer, initiator and crosslinker until an equilibrium swelling was achieved. Then, acrylamide in the film was polymerized at about 70°C. The PAAm fraction in IPN depends on the type of SPU used and increases with increasing acrylamide concentration in several swelling solvents used for IPN's preparation for a SPU. Also the water absorption capability of IPN becomes large as the PAAm fraction increases.View full abstractDownload PDF (830K) -
Masato TAKAHASHI, Kasane UNO1990 Volume 47 Issue 5 Pages 439-443
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe phase separation process of polystyrene (PS) /poly (metylphenylsiloxane) (PMPS) liquid mixtures was investigated by light scattering. In order to test the scaling law S (k, t) =km-3s (k/km), which represents the self-similarity of the phase structure, we tried to superpose the measured structure function S (k, t) . Here k is the wave nunber, km the wave number yielding the maximum intensity and s (k/km) the scaled structure function independent of time t. The superposition for the critical composition was fairly good. However, S (k, t) for off-critical compositions gradually changed with t, coming to have a broader peak, so that the superposition was not so good. The observed exponent describing the wave number dependence at k>km was near the one given by Porod's law, i. e., -4, for both the critical and off-critical compositions. However, the conservation law ∫∞0 [k4s (k, t) -2πA] dk=0 proposed by Tomita, qualitatively held only for off-critical compositions.View full abstractDownload PDF (779K) -
Jun-ichi SUENAGA, Eiji FUJITA1990 Volume 47 Issue 5 Pages 445-449
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSPolymer blends of a semi-aromatic liquid crystal polyester (LCP) and a wholly aromatic LCP were investigated in order to improve thermal endurance properties of a semi-aromatic LCP. The heat deflection temperature of the semi-aromatic LCP was improved by blending with wholly-aromatic LCP. A process consisting of blending at a low temperature where only the semi-aromatic LCP melts and injection molding at a high temperature where both LCPs melt could overcome the thermal degradation of the blends.View full abstractDownload PDF (1390K) -
Tomoo SHIOMI, Masao TOHYAMA, Masato SUZUKI, Kiyokazu IMAI1990 Volume 47 Issue 5 Pages 451-454
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSTemperature dependence of the interaction parameterχwas calculated over all the copolymer compositions for the random copolymer blends of poly (vinyl acetate-co-vinyl chloride) and poly (isobutyl methacrylate-co-n-butyl methacrylate). The two polymers are immiscible in a certain range of copolymer compositions, though any binary mixture of the corresponding homopolymers is miscible. The temperature dependences of χ were monotonically increasing functions over all the copolymer compositions while the sign of χ changed with the copolymer composition from negative→positive→negative at a certain temperature. Since the exchange enthalpy parameters between the copolymer components used here were determined from the experimental results for miscibility in the present blends with finite molecular weights, these results for the temperature dependence of χ need further examination.View full abstractDownload PDF (687K) -
Masato TAKAHASHI, Nobuyuki HARASAWA, Hirohisa YOSHIDA1990 Volume 47 Issue 5 Pages 455-458
Published: May 25, 1990
Released on J-STAGE: March 15, 2010
JOURNAL FREE ACCESSThe effects of poly (methyl methacrylate) (PMMA) tacticity and molecular weight on the isothernal crystallization behavior of poly (ethylene oxide) (PEO) in PEO/ PMMA blend systems were investigated by a differential scanning calorimeter. Two kinds of atactic PMMA, isotactic PMMA, and syndiotactic PMMA were used as blend materials. The rate of crystallization became slower with increasing PMMA content and molecular weight. Irrespective of PMMA molecular weight, the heat of fusion decreased with increasing PMMA content and depended on the PMMA tacticity. The apparent activation energy of crystallization of isotactic, syndiotactic, and atactic PMMA blend systems decreased in that order, irrespective of PMMA content and molecular weight.View full abstractDownload PDF (677K)
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