Polymer Journal - Vol. 37, No. 7 (July, 2005)

Polymer Journal
Vol. 37, No. 7 (July, 2005)

[Regular Article] Web Release Date: July 15, 2005

453-463 Asymmetric Anionic Polymerizations of (R)-N-Maleoyl-d-Phenylglycine Alkyl Esters and Optical Resolution Using Their Polymers
T. Oishi, Y. Zhang, T. Fukushima, and K. Onimura
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Asymmetric anionic polymerizations of (R)-N-maleoyl-d-phenylglycine methyl ester ((R)-MPGMI) and (R)-N-maleoyl-d-phenylglycine benzyl ester ((R)-BnPGMI) were carried out with organometal or organometal/ligand complex as initiators. Highly optically active poly((R)-MPGMI)s were obtained using Bnbox, but poly((R)-BnPGMI)s did not show highly optical activity ascribed to the bulkier benzyl in the ester group. The chiroptical properties and structures of these polymers were investigated by CD, XRD, and ¹³C NMR measurements. The CSPs of HPLC prepared with the obtained poly((R)-MPGMI)s showed good chiral discriminability to many racemates.

[Regular Article] Web Release Date: July 15, 2005

464-470 Synchrotron SAXS Studies on Morphology Formation in a Binary Blend of Poly(ε-caprolactone) Homopolymer and Poly(ε-caprolactone)-block-Polybutadiene Copolymer
M. Akaba and S. Nojima
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The process of morphology formation in a binary blend of poly(ε-caprolactone) homopolymer (PCL) and poly(ε-caprolactone)-block-polybutadiene copolymer (PCL-b-PB) has been investigated by synchrotron small-angle X-ray scattering (SR-SAXS), where an UCST-type phase separation between PCL and PCL-b-PB and the crystallization of PCL chains may work simultaneously to exhibit a complicated morphology formation. Time-resolved SAXS curves (Figure) show that total morphology formation is driven by the crystallization of PCL chains, where a crystallized PCL region always coexists with a crystallized PCL-b-PB region and the volume ratio of two regions is constant throughout.

[Regular Article] Web Release Date: July 15, 2005

471-479 Morphology Control of Poly(p-mercaptobenzoyl) by Modification of Oligomer End-group
K. Kimura, D. Nakajima, K. Kobashi, S. Kohama, T. Uchida, and Y. Yamashita
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The polymerization of S-acetyl-4-mercaptobenzoic acid in liquid paraffin at 260–300 °C afforded poly(p-mercaptobenzoyl)(PMB) whiskers by the reaction-induced crystallization of oligomers, whereas the polymerization of S-propionyl-4-mercaptobenzoic acid, S-butyryl-4-mercaptobenzoic acid and S-valeryl-4-mercaptobenzoic acid yielded PMB microspheres. The microspheres were formed by the liquid–liquid phase separation of oligomers induced by the longer acyl end-groups. In contrast to this, the polymerizations of their dimers afforded needle-like and slab-like crystals instead of microspheres. The morphology of PMB could be controlled by the chemical modification of oligomer end-groups.

[Regular Article] Web Release Date: July 15, 2005

480-488 pH-Responsive Micellization of Amine-Containing Cationic Diblock Copolymers Prepared by Reversible Addition-Fragmentation Chain Transfer (RAFT) Radical Polymerization
S. Yusa, Y. Konishi, Y. Mitsukami, T. Yamamoto, and Y. Morishima
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A series of poly([3-(methacryloylamino)propyl]trimethylammonium chloride)-block-poly(2-(diethylamino)ethyl methacrylate) (pMAPTAC_m–DEAEMA_n) of different block lengths were prepared by controlled radical polymerization based on reversible addition-fragmentation chain transfer (RAFT). The pMAPTAC_m–DEAEMA_n block copolymers exhibited pH-induced micelle formation and dissociation, which was investigated by ¹H NMR, QELS, SLS, and fluorescence techniques. The pH-induced formation and dissociation of micelle were completely reversible. Since the block copolymer micelles formed at basic pHs are able to incorporate hydrophobic small molecules, they are expected to provide useful materials for applications in broad areas.

[Regular Article] Web Release Date: July 15, 2005

489-497 Microstructure and Thermal Behavior of Poly(o-anisidine)/Poly(ethylene terephthalate) Composite
P. Santhosh, A. I. Gopalan, M. Sankarasubramanian, T. Mathanmohan, T. Vasudevan, and K.-P. Lee
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The film of poly(ethylene terephthalate) (PET)/poly(o-anisidine) (POA) composite with 3.5 wt. % of POA has a conductivity of 15.6 K Ω^-1 cm^-1. The shifts in the frequencies of the bands in the infra-red and UV–vis spectra for the composites inform the molecular level interactions between the components of the composite. The amorphous region of the PET is affected by the formation of cross-links between POA and PET. The composite can be reversibly doped and de-doped. AFM topography shows the genuine composite formation.

[Regular Article] Web Release Date: July 15, 2005

498-505 Molecular Origin for the Thermal Stability of S-88 Gum Produced by Pseudomonas ATCC 31554
M. Tako and H. Tamaki
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The thermal stability for viscosity and dynamic viscoelasticity of S-88 gum produced by Pseudomonus ATCC 31554 were analysed with respect to its association characteristics, in comparison with those of deacetylated gellan, welan and rhamsan gum, the structure of which were similar to that of the former. Intramolecular association of S-88 gum were proposed.

[Regular Article] Web Release Date: July 15, 2005

506-511 Preparation and Characterization of Cyclic Polystyrenes
D. Cho, K. Masuoka, K. Koguchi, T. Asari, D. Kawaguchi, A. Takano, and Y. Matsushita
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Macrocyclic polystyrenes with various molecular weight were prepared by the reaction of linear polystyrene having two end vinyl groups and potassium naphthalenide as a coupling agent. Side reactions produced higher molecular weight polycondensates and linear precursors in addition to the designed molecules. After prep-scale SEC fractionation, the purity of SEC-fractionated cyclic polystyrenes was rigorously examined by interaction chromatography (IC). Highly pure cyclic polymers were obtained, though high molecular weight cyclic polymers contain very small amount of linear precursors (<5%).

[Regular Article] Web Release Date: July 15, 2005

512-516 Thermal Polymerization of 1,2-Dithiane
K. Endo, T. Shiroi, and N. Murata
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Thermal polymerization of six-membered cyclic disulfide, 1,2-dithiane (DT) was investigated under various polymerization conditions. The polymerization of DT did not occur at low monomer concentration. The propagation involves a radical intermediate. The relationships between polymer yields and molecular weight of polymers suggest that the cyclic polymer is formed by back biting mechanism in the polymerization of DT.

[Regular Article] Web Release Date: July 15, 2005

517-521 A Novel Low Temperature Curable Photosensitive Polybenzoxazole
F. Toyokawa, Y. Shibasaki, and M. Ueda
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A novel positive-tone photosensitive polybenzoxazole (PBO) for low temperature cyclization has been developed. The photosensitive polymer was formulated with poly(o-hydroxyamide) (PHA-6F), a dissolution inhibitor (S-DNQ), and a photo- and thermoacid generator (PTMA) in a weight ratio of 15:3:2. A clear positive PBO image featuring 8 μm line-and-space was obtained, when a 2.1 μm-photosensitive film was prebaked at 120 °C, irradiated with 365 nm light, developed with an alkaline developer, washed with an acetic acid solution, and cured at 250 °C for 10 min.

[Regular Article] Web Release Date: July 15, 2005

522-528 A Morphological Study of the Effect of Carbon Nanotube Filler on Tribology of Phenol/Formaldehyde Resin-based Composites
A. Igarashi, T. Terasawa, M. Kanie, T. Yamanobe, and T. Komoto
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Phenol/formaldehyde resin-based composites with highly dispersed carbon nanotubes were prepared via stepwise polymerizations. Tribological properties measured in the friction machine are investigated with reference to the morphology of the as-prepared resin and fractioned surfaces of the resin as studied by SEM, TEM and so on.

[Regular Article] Web Release Date: July 15, 2005

529-534 Translational Diffusion Coefficient of Polystyrene Polymacromonomers. Dependence on Side-Chain Length
T. Hokajo, Y. Hanaoka, Y. Nakamura, and T. Norisuye
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Dynamic light scattering measurements have been made to determine the translational diffusion coefficient of F15 (circles), F33 (squares), and F65 (unfilled triangles) in cyclohexane at 34.5 °C and F65 in toluene (filled circles) at 15 °C as functions of the weight-average molecular weight M_w. The numbers of styrene residues in a side chain for F15, F33, and F65 are 15, 33, and 65, respectively. It is shown that the hydrodynamic radii R_H for these polymers are explained by the unperturbed wormlike chain by considering the effects from chain ends.

[Regular Article] Web Release Date: July 15, 2005

535-540 Nuclear Magnetic Relaxation of Poly(n-hexyl isocyanate) in Dilute Solution. Effects of Chain Stiffness
M. Nakatsuji, T. Yoshizaki, and H. Yamakawa
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The spin–lattice relaxation time T₁ (

), spin–spin relaxation time T₂ (

), and nuclear Overhauser enhancement NOE (

) were determined for poly(n-hexyl isocyanate) in n-hexane at 25 °C. It is shown that the theory developed for the generalized Kratky–Porod wormlike chain (heavy curves) as a special case of the helical wormlike chain may almost quantitatively explain the behavior of the present data. A comparison is also made of them with Woessner's theoretical values (light curves) for the rigid prolate spheroid.

Web Release Date: July 15, 2005

541-544 Magnetic Effects on Extrudate Swell of a Polystyrene Melt in Capillary Extrusion Dies
N. Intawong, T. Kimura M. Tamura, L. Xiaojun, and N. Sombatsompop
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Extrudate swell of a polystyrene melt in steel and stainless capillary extrusion dies exposed to magnetic field was studied. A small but significant magnetic effect was observed in spite of relatively large scattering of the experimental data. The swell was enhanced for a steel die and reduced for a stainless die about 2–5% by the exposure to the magnetic field. Possible mechanisms were proposed on the basis of the comparison of the magnetic energy and the elastic energy stored by deformation of the polymer melt.