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New Aromatic Diacids Containing the Trifluoromethyl Group and their Polyamides
Polymer Research Group, Department of Chemistry, Southwest Texas State University, San Marcos, TX 78666, USA
NASA Langley Research Center, Hampton, VA 23665, USA A series of new fluorinated, high-temperature polymers has been prepared from 1, 1, - bis(p-carboxyphenyl)-2, 2, 2-trifluoroethanol (3FOH). This diacid was synthesized by oxidation of 1, 1-di(p-tolyl)-2, 2, 2-trifluoroethanol, which was obtained from p-bromotoluene and ethyl trifluoroacetate. The 3FOH was also reacted with dimethyl sulphate to yield 1-methoxy-1, 1- bis(p-carboxyphenyl)-2, 2, 2-trifluoroethane (3FM), and with SOCl2 to produce 1-chloro-1, 1- bis(p-chloroformylphenyl)-2, 2, 2-trifluoroethane (3FCl). These two diacids, as the acid chlorides, were polymerized with six aromatic and four aliphatic diamines to produce polyamides which had viscosities ranging from 0.32 to 1.52 dl g–1, thermal stabilities up to 518 °C in nitrogen and glass transition temperatures from 165 °C to 337 °C. The dielectric constants of these polyamides ranged from 2.64 to 2.99. The 3FM- and 3FCl-containing polyamides were compared with the 6F (hexafluoroisopropylidene) analogues and found to be somewhat less thermally stable and had equal or lower Tgs.
High Performance Polymers, Vol. 9, No. 3,
323-332 (1997) |
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