caa a22 4500 605466920 CHVBK 20210128100309.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s00397-015-0871-x doi (NATIONALLICENCE)springer-10.1007/s00397-015-0871-x Rheological characterization of H-shaped poly(methyl methacrylate)s [Elektronische Daten] [Koji Ogura, Kohei Morioka, Shu-Yao Hsu, Yoshinobu Tsujii, Manfred Wagner] Investigation of the extensional flow behavior and development of constitutive equations for well-characterized H-shaped polymers is important both from an industrial and academic viewpoints. For H-shaped polymer systems, little is known about the extensional flow behavior at constant strain rates. We synthesized H-shaped poly(methyl methacrylate)s (PMMAs) with narrow molecular weight distributions and various ratios of the molecular weight of the backbone, M b, to that of the arm, M a, by atom transfer radical polymerization. However, 1H NMR spectroscopy showed that the resulting PMMA samples contained substantial amounts of linear and star topologies. In spite of the limited purity of the H-shaped PMMAs obtained, the rheological properties in linear viscoelasticity and uniaxial extensional flow revealed interesting results. The zero-shear viscosity of model PMMAs was well described by an exponential relation of the molecular weight. Qualitative agreement was found between the experimental linear-viscoelastic behavior and predictions of the model of McLeish et al. (Macromolecules 32: 6734-6758, 1999) for H-shaped polymers. The elongational flow behavior was also analyzed by the molecular stress function (MSF) model. Surprisingly, the strain-hardening effect for all investigated model PMMAs was weaker than that for pom-pom polystyrene polymers. Springer-Verlag Berlin Heidelberg, 2015 H-shaped polymer nationallicence Rheology nationallicence Molecular stress function model nationallicence Uniaxial extension nationallicence Strain hardening nationallicence Poly(methyl methacrylate) nationallicence Ogura Koji Basic Chemicals Research Laboratory, Sumitomo Chemical Co., Ltd, 5-1, Sobiraki-cho, 792-8521, Niihama City, Ehime, Japan aut Morioka Kohei Basic Chemicals Research Laboratory, Sumitomo Chemical Co., Ltd, 5-1, Sobiraki-cho, 792-8521, Niihama City, Ehime, Japan aut Hsu Shu-Yao Institute for Chemical Research, Kyoto University, 611-0011, Uji, Kyoto, Japan aut Tsujii Yoshinobu Institute for Chemical Research, Kyoto University, 611-0011, Uji, Kyoto, Japan aut Wagner Manfred Chair of Polymer Engineering/Polymer Physics, Berlin Institute of Technology (TU Berlin), Fasanenstrasse 90, 10623, Berlin, Germany aut Rheologica Acta Springer Berlin Heidelberg 54/9-10(2015-10-01), 793-804 0035-4511 54:9-10<793 2015 54 397 https://doi.org/10.1007/s00397-015-0871-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00397-015-0871-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ogura Koji Basic Chemicals Research Laboratory, Sumitomo Chemical Co., Ltd, 5-1, Sobiraki-cho, 792-8521, Niihama City, Ehime, Japan aut NATIONALLICENCE 700 1- Morioka Kohei Basic Chemicals Research Laboratory, Sumitomo Chemical Co., Ltd, 5-1, Sobiraki-cho, 792-8521, Niihama City, Ehime, Japan aut NATIONALLICENCE 700 1- Hsu Shu-Yao Institute for Chemical Research, Kyoto University, 611-0011, Uji, Kyoto, Japan aut NATIONALLICENCE 700 1- Tsujii Yoshinobu Institute for Chemical Research, Kyoto University, 611-0011, Uji, Kyoto, Japan aut NATIONALLICENCE 700 1- Wagner Manfred Chair of Polymer Engineering/Polymer Physics, Berlin Institute of Technology (TU Berlin), Fasanenstrasse 90, 10623, Berlin, Germany aut NATIONALLICENCE 773 0- Rheologica Acta Springer Berlin Heidelberg 54/9-10(2015-10-01), 793-804 0035-4511 54:9-10<793 2015 54 397