Theoretical approaches to the mechanical relaxation mechanisms in semicrystalline polymers |
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| Authors: | Naonori Yoshioka Yutaka Obata Hiromichi Kawai |
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| Institution: | 1. Department of Polymer Chemistry , Faculty of Engineering , Kyoto University, Kyoto, Japan;2. Research Laboratory , Mitzubishi Rayon Co., Ltd. , Ohtake, Hiroshimaken, Japan;3. Department of Polymer Chemistry , Faculty of Engineering , Kyoto University, Kyoto, Japan |
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| Abstract: | Two kinds of relaxation mechanisms in semicrystalline polymers, i.e., the primary relaxation mechanism attributed to the noncrystalline phase and the crystalline relaxation mechanism attributed to the crystalline phase, are explained, respectively, in terms of (1) a modified Bueche's model of a one-dimensional vibrating string taking higher-order potential effects into account and (2) Montroll's model of a plane lattice in the form of a vibrating membrane. The modified Bueche's theory of a one-dimensional vibrating string gives a slope in the wedge portion of the relaxation time spectrum of less than – 1/2, when one assumes that the force constants of higher-order potential effects of intra- and intermolecular interaction are negative. The plane lattice model of a membrane vibrating in a lateral as well as in a longitudinal fashion gives a box-type relaxation time spectra over almost the same relaxation time range. |
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| Keywords: | atactic oligomeric PHB-diol Boon–Azcue equation crystallization kinetics equilibrium melting temperature polyhydroxybutyrate spherulitic growth rate |
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