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Fast and eco-friendly synthesis of novel soluble thermally stable poly(amide-imide)s modified with siloxane linkage with reduced dielectric constant under microwave irradiation in TBAB, TBPB and MeBuImCl via isocyanate method

Authors

  • Fatemeh Rafiemanzelat,

    Corresponding author
    1. Department of Chemistry, Organic Polymer Chemistry Research Laboratory, University of Isfahan, Isfahan 81746-73441, Iran
    • Department of Chemistry, Organic Polymer Chemistry Research Laboratory, University of Isfahan, Isfahan 81746-73441, Iran
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  • Seyyed Mahmood Khoshfetrat,

    1. Department of Chemistry, Organic Polymer Chemistry Research Laboratory, University of Isfahan, Isfahan 81746-73441, Iran
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  • Majid Kolahdoozan

    1. Department of Chemistry, Organic Polymer Chemistry Research Laboratory, Islamic Azad University, Shahreza Branch, Shahreza, Isfahan, 311-86145, I.R. Iran
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Abstract

A new series of poly(amide-imide)s (PAI) modified with a siloxane linkage was synthesized under microwave radiation in ionic liquids and organic salts via the isocyanate method. The polymerization reactions of a novel siloxanic diacid monomer with 4,4′-methylene-bis(4-phenylisocyanate) MDI were studied in ammonium, phosphonium, and imidazolium-type organic salts. These poly(amide-imide-siloxane)s (PAI-Si)s were obtained with high yields and good inherent viscosities ranging from 0.30 to 0.55 dL/g. The normally high softening temperatures and poor solubility of PAIs in organic solvents were improved via the incorporation of the flexible siloxane segments into the polymer backbone. The PAI-Sis showed glass transition temperatures around 100°C and their 10% mass loss was about 300°C. They have a char yield in the range of 30–40% at 800°C. Calculated limiting oxygen index values of the polymers were about 30; therefore, they can be considered as self-extinguishing. The dielectric constants of these silane-containing PAIs (2.5) are lower than common siloxane-free polyimides (∼ 3). Their good thermal stability, enhanced solubility, and low dielectric constants suggest they may function as electrical insulators. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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