Journal of Polymer Science Part B: Polymer Physics

Cover image for Vol. 51 Issue 8

15 April 2013

Volume 51, Issue 8

Pages i–ii, 621–697

  1. Cover Image

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Full Papers
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      Cover Image, Volume 51, Issue 8 (pages i–ii)

      Article first published online: 5 MAR 2013 | DOI: 10.1002/polb.23283

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      In the work by Thi Thu Thao Ho et al. on page 638, composite films of nanofibrillated cellulose (NFC) and vermiculite are prepared and subsequently treated with liquid ammonia. Upon treatment, the crystal structure of cellulose both in the presence and absence of vermiculite changes from cellulose I to III. The structure of trimethylammonia-modified (TMA)-NFC/vermiculite films before and after ammonia treatment is the most dense and most homogeneous due to electrostatic attraction between ammonium groups of TMANFC and anionic layers of vermiculite. Treatment of composite films with ammonia leads to a significant decrease in water vapor permeation. Therefore, the composites have potential applications as eco-friendly barriers for food packaging. The cover is a SEM image of a TMA-NFC/vermiculite dried suspension (mass ratio = 1:1). Fine vermiculite platelets are found to distribute homogeneously in the cationic NFC network.

  2. Reviews

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    3. Reviews
    4. Full Papers
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      Thermally induced shape-memory effects in polymers: Quantification and related modeling approaches (pages 621–637)

      Matthias Heuchel, Tilman Sauter, Karl Kratz and Andreas Lendlein

      Article first published online: 6 FEB 2013 | DOI: 10.1002/polb.23251

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      Thermally induced shape-memory effects (SME) of polymers are quantified by cyclic thermomechanical tests. These data sets serve as basis to understand SMEs and to create appropriate modeling descriptions. Here, characterization methods for dual-, triple-, and multi-shape polymers as well as materials that exhibit a temperature-memory effect are reviewed together with recently developed thermomechanical modeling approaches to simulate such experiments.

  3. Full Papers

    1. Top of page
    2. Cover Image
    3. Reviews
    4. Full Papers
    1. Liquid ammonia treatment of (cationic) nanofibrillated cellulose/vermiculite composites (pages 638–648)

      Thi Thu Thao Ho, Tanja Zimmermann, Walter Remo Caseri and Paul Smith

      Article first published online: 8 JAN 2013 | DOI: 10.1002/polb.23241

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      Composite films of nanofibrillated cellulose (NFC) and vermiculite have been prepared and subsequently treated with liquid ammonia, resulting in film cross-sections with highly oriented layered structures. The structure of films before and after ammonia treatment is densest and most homogeneous in trimethylammonium-modified (TMA)- NFC/vermiculite films. The composites do not swell in ammonia due to electrostatic attraction between ammonium groups of TMA-NFC and anionic layers of vermiculite. The composites have potential applications as eco-friendly barriers for food packaging.

    2. Charge transport study of semiconducting polymers and their bulk heterojunction blends by capacitance measurements (pages 649–658)

      Kevin K. H. Chan, S. W. Tsang, Harrison K. H. Lee, F. So and S. K. So

      Article first published online: 8 JAN 2013 | DOI: 10.1002/polb.23236

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      In this contribution, charge transport properties of thin film polymers and their bulk heterojunction (BHJ) blends are probed by capacitance measurements. Six semiconducting polymers—P3HT, MDMO-PPV, PFB, TFB, PCDTBT, and PVK—were investigated by admittance spectroscopy, a powerful tool for the extraction of hole mobilities and transport parameters. For films of P3HT and PCDTBT, electron leakage occurs and obscures the extraction of hole transit times. To prevent this, a thin electron blocking and trapping interlayer between the BHJ and gold cathode is added.

    3. Enhanced mechanical property of chitosan via blending with functional poly(ε-caprolactone) (pages 659–667)

      Chunhua Gu, Weibin Shi and Meidong Lang

      Article first published online: 27 DEC 2012 | DOI: 10.1002/polb.23237

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      Biodegradable polymers such as poly(ε-caprolactone) and chitosan are part of an important class of biomaterials useful as tissue engineering scaffolds because they are biologically and chemically similar to natural tissues. To overcome issues such as slow degradation rate and low mechanical strength, blending such polymers is relatively simple and economical. In this work, chitosan was blended with poly(ε-caprolactone-co-2-oxepane-1,5-dione), and evaluation of tensile properties indicated a remarkable improvement over chitosan alone due to a suppression of chitosan crystallinity.

    4. Effect of low-temperature processing on dry film photoresist properties for flexible electronics (pages 668–679)

      Andrés Vásquez Quintero, Danick Briand and Nico F. de Rooij

      Article first published online: 7 JAN 2013 | DOI: 10.1002/polb.23240

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      Lamination of PerMX dry film photoresist at low temperatures on flexible polymers is reported. Mechanical properties, adhesion behavior, and mechanical robustness are assessed for different processing temperatures. Because of its flexible nature, adhesive properties, and patternability, the material is envisaged to be widely used in flexible and printed electronics applications such as encapsulation and integration of foil/silicon components and electrical interconnections.

    5. Miscibility in crystalline/amorphous blends of poly(3-hydroxybutyrate)/DGEBA (pages 680–686)

      Leonel Silva, Sebastián Tognana and Walter Salgueiro

      Article first published online: 8 JAN 2013 | DOI: 10.1002/polb.23242

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      Polymer blends offer diverse benefits: improvements in the final properties of polymer-based materials, a reduction in costs and the use of environmentally friendly materials. Blend miscibility is central to the development of microstructure and morphology. In this work, using calorimetry, the blend poly(3-hydroxybutyrate)/diglycidyl ether of bisphenol A (DGEBA) was found to be miscible. Likewise, from the results of small-angle X-ray scattering, the lamellar structure of the crystalline poly(3-hydroxybutyrate) was observed to suffer changes due to the insertion of amorphous DGEBA.

    6. A critical analysis of the effect of crosslinking on the linear viscoelastic behavior of styrene–butadiene rubber and other elastomers (pages 687–697)

      Rasika Prabhu, Rasmus Klitkou, Grigori A. Medvedev and James M. Caruthers

      Article first published online: 24 JAN 2013 | DOI: 10.1002/polb.23243

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      Time–temperature superposition (TTS) is used to analyze linear viscoelastic behavior of elastomer systems with varying degrees of crosslinking. Linear viscoelastic behavior in dynamic shear and tensile creep at temperatures from −30 to 70 °C is measured for SBR elastomer cured with dicumyl peroxide to crosslinking densities between 0 and 23.5×10−5 mol/cm3. To achieve the TTS of the storage, loss, and δ isotherms in the lightly crosslinked SBR, an anomalous vertical shift is required in the narrow temperature range from 10 to 30 °C.

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