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Dielectric properties of copolymers based on cyano monomers and methyl α-acetoxyacrylate

Authors

  • Mustapha Raihane,

    Corresponding author
    1. Laboratoire de Chimie Organométallique et Macromoléculaire—Matériaux Composites, Université Cadi-Ayyad, Faculté des Sciences et Techniques, BP 549, 40000 Marrakech, Morocco
      Mustapha Raihane, Laboratoire de Chimie Organométallique et Macromoléculaire—Matériaux Composites, Université Cadi-Ayyad, Faculté des Sciences et Techniques, BP 549, 40000 Marrakech, Morocco. E-mail: m.raihane@fstg-marrakech.ac.ma
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  • Amar Zerroukhi,

    1. Université de Lyon, F-69003, Département de Chimie, Université Jean Monnet Saint-Etienne, F-42023, France
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  • Hamid Kaddami,

    1. Laboratoire de Chimie Organométallique et Macromoléculaire—Matériaux Composites, Université Cadi-Ayyad, Faculté des Sciences et Techniques, BP 549, 40000 Marrakech, Morocco
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  • Mohammed Lahcini,

    1. Laboratoire de Chimie Organométallique et Macromoléculaire—Matériaux Composites, Université Cadi-Ayyad, Faculté des Sciences et Techniques, BP 549, 40000 Marrakech, Morocco
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  • Gisèle Boiteux

    1. IMP-Laboratoire des Matériaux Polymères et Biomatériaux, UMR IMP CNRS 5627, Domaine Scientifique de la Doua, Bât. ISTIL, 15 Bd. A. Latarget, 62622 Villeurbanne Cedex, France
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Mustapha Raihane, Laboratoire de Chimie Organométallique et Macromoléculaire—Matériaux Composites, Université Cadi-Ayyad, Faculté des Sciences et Techniques, BP 549, 40000 Marrakech, Morocco. E-mail: m.raihane@fstg-marrakech.ac.ma

Abstract

With the aim of developing dielectric polymers containing CN groups with strong dipole moment, alternating and statistical copolymers of the cyano monomers vinylidene cyanide (VCN), acrylonitrile and methacrylonitrile with methyl α-acetoxyacrylate (MAA) were synthesized and characterized. The copolymer's composition and microstructure were analysed by NMR spectroscopy, SEC and elemental analysis. The reactivity ratios calculated from the Qe Alfrey–Price parameters for these copolymers indicated the alternating and statistical structures confirmed by NMR analysis. The copolymers have glass transition temperatures Tg in the range 83–146 °C and are stable up to 230 °C. The thermal stability of the copolymers depends on the nature of the cyano monomers. Their molecular dynamics were investigated by dielectric relaxation spectroscopy. We revealed a weak relaxation β at sub-Tg temperature for poly(VCN-co-MAA) usually originating from molecular motions that are restricted to the scale of a few bond lengths. Strong α-relaxation processes occurred above Tg for these copolymers. This primary relaxation was associated with cooperative movements of the polar groups (CN) at the time of mobility of the principal chains. The activation energy of the α-relaxation process was also calculated. The values of the dielectric increment Δε for these copolymers were determined by Cole–Cole plots and indicated that the copolymers exhibit interesting dielectric properties compared with similar cyano materials. The polarity–permittivity relationship was also established. © 2012 Society of Chemical Industry

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