Journal of Polymer Science Part B: Polymer Physics

Cover image for Vol. 50 Issue 18

15 September 2012

Volume 50, Issue 18

Pages i–ii, 1271–1327

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      Cover Image, Volume 50, Issue 18 (pages i–ii)

      Version of Record online: 6 AUG 2012 | DOI: 10.1002/polb.23143

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      Reaction-induced crystallization during polymerization is an attractivemethod for the morphosynthesis of poorly processable rigid polymers, because it is not limited by the intractability of polymers. This method is applied to morphosynthesis of poly(ether imide)s by Takashi Sawai, Kanji Wakabayashi, Shinichi Yamazaki, Tetsuya Uchida, and Kunio Kimura on page 1293. The fibrillar crystals of poly[4-(1,4-phenylene)oxyphthalimide] are formed as the precipitates. Wide varieties of one-dimensional structures of poly[4-(1,4-phenylene)oxy phthalimide-co-4-phthalimide] are synthesized such as ribbons, cones, rods and fibers, depending on the copolymerization ratio. The morphology of the poly(ether imide)s can be controlled by not only the polymerization condition but also the aid of copolymerization.

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    1. Dependence of dielectric, ferroelectric, and piezoelectric properties on crystalline properties of p(VDF-co-TrFE) copolymers (pages 1271–1276)

      Weimin Xia, Zhuo Xu, Qiuping Zhang, Zhicheng Zhang and Yuanqing Chen

      Version of Record online: 30 JUL 2012 | DOI: 10.1002/polb.23125

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      High crystallinity and large crystal grain size, which may be controlled by thermal processing, were shown to improve the ferro-electric and piezoelectric properties of a ferroelectric polymer P(VDF-co-TrFE). Compared to the cooled and quenched samples, thick annealed P(VDF-co-TrFE) films have the largest saturated (Ps = 10.5 μC/cm2) and remnant polarizations (Pr = 8 μC/cm2). After being polarized at high temperature, the highest piezoelectric value in longitudinal thickness mode (d33 = −25 pC/N) was obtained in the resultant films.

    2. Stereochemical heterogeneity of biodegradable poly(L-lactide) homopolymer as revealed by temperature rising elution fractionation and successive self-nucleation/annealing thermal fractionation (pages 1277–1285)

      Jun Luo, Fei Huo, Hui Lin, Zhouli Lin, Zhengjian Chen, Fang Yuan, Hongliang Jiang, Hongjun Wang, Kehua Tu, Dingrong Liu, Songwei Tan and Li-Qun Wang

      Version of Record online: 30 JUL 2012 | DOI: 10.1002/polb.23127

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      Biodegradable poly(L-lactide) is successfully separated with temperature rising elution fractionation (TREF) in a quantitative manner for the first time. The stereochemical heterogeneity of PLLA fractions is investigated with successive self-nucleation/annealing thermal fractionation. This work provides a good example for extending the application of TREF. It is expected that TREF will be applied to more and more other biodegradable polyester with similar chain structure.

    3. Diffusion of dextran within poly(methacrylic acid) hydrogels (pages 1286–1292)

      Ateyyah M. AL-Baradi, Matthew Mears, Richard A. L. Jones and Mark Geoghegan

      Version of Record online: 9 JUL 2012 | DOI: 10.1002/polb.23120

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      The diffusion of molecules trapped within responsive hydrogels can be controlled by changing environmental conditions. Here, it is shown that poly(methacrylic acid) hydrogels respond to temperature, salt, and pH to alter the diffusion coefficient of dextran within the gel. The presence of ions in the surrounding environment cause significant swelling of the gel, with low ion concentrations providing the largest effect on both the mesh size of the gel and the diffusion of the dextran molecules.

    4. Morphosynthesis of poly[4-(1,4-phenylene)oxyphthalimide] and copolymers prepared by reaction-induced crystallization during polymerization (pages 1293–1303)

      Takashi Sawai, Kanji Wakabayashi, Shinichi Yamazaki, Tetsuya Uchida and Kunio Kimura

      Version of Record online: 20 JUL 2012 | DOI: 10.1002/polb.23122

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      Controlling the morphology of rigid aromatic poly(ester imide)s by conventional techniques is difficult because of their poor processability. Morphosynthesis of aromatic polyetherimides was examined by using reaction-induced crystallization during the polymerization. The morphology was controlled by the polymerization conditions and the copolymerization, and one-dimensional structural products such as fibers and cone-like crystals were obtained as precipitates. Molecular alignment was also controlled by the aid of templates.

    5. Processing and characterization of oriented electrospun poly(vinylidene fluoride) mats (pages 1304–1311)

      Thiago Manha Gasparini, Rosário Elida Suman Bretas, Aline Bruna da Silva and Rinaldo Gregorio Jr.

      Version of Record online: 23 JUL 2012 | DOI: 10.1002/polb.23123

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      The orientation of electrospun fibers is important in applications where anisotropic properties are significant, as in electronic devices. Poly(vinylidene fluoride) mats containing highly oriented nanofibers were electrospun using a disk collector rotating at 4000 rpm and a device that reduces the influence of air displacement during nanofiber orientation. The fibers had mostly β-phase and chains oriented along the fiber axis in both crystalline and amorphous regions. The mats exhibited higher permittivity and remnant polarization and lower coercive field in relation to those electrospun at 2000 rpm.

    6. Aggregation behavior of organic-soluble semi-aromatic polyimides in N-methylpyrrolidone systems (pages 1312–1320)

      Yoichi Ogata, Kenji Fujita, Megumi Nakanishi, Motoki Okaniwa and Manabu Sekiguchi

      Version of Record online: 30 JUL 2012 | DOI: 10.1002/polb.23124

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      Low solubility of polymers is closely related to their preservation stability and is often accompanied by aggregation. To limit aggregation behavior of organic-soluble polyimides, incorporation of substituent groups contributing to solubilization is an effective method to improve the preservation stability of polyimide solutions. Here, the solution properties and aggregation behavior of organic-soluble semi-aromatic polyimides as a function of imidization degree are discussed on the basis of the characterization results of both static light scattering and dynamic light scattering.

    7. Isotropic–nematic phase separation and demixing in mixtures of spherical nanoparticles with length-polydisperse nanorods (pages 1321–1327)

      Micah J. Green

      Version of Record online: 23 JUL 2012 | DOI: 10.1002/polb.23126

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      Although liquid-crystalline phase formation has been observed for rod-like polymers for many years, anisotropic nanomaterials are driving novel developments in the theoretical descriptions of these systems. This work addresses the important issue of the addition of spherical nanoparticles to length-polydisperse systems of nanorods. A new formulation of Onsager theory has been developed for mixtures of length-polydisperse rods and spheres. The effects of nanorod and nanoparticle geometry on phase diagram shape are investigated.

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