IMIDE-ARYL ETHER BENZOTHIAZOLES

Novel imide-aryl ether benzothiazole copolymers were prepared and thei r morphology and mechanical properties investigated. Diamines containi ng preformed benzothiazole rings were prepared and used in conventiona l polyimide syntheses. The preparation of these diamines involved the nucleophilic aromatic substitution reaction of 2,6-bis(4-fluorophenyl) benzo[1,2,4,5]bisthiazole with either 3- or aminophenol in the presenc e of K2CO3 in N-methyl-2-pyrrolidone to afford s(4-aminophenoxy-4-phen yl)benzo[1,2,4,5]dithiazole and (3-aminophenoxy-4-phenyl)benzo[1,2,4,5 ]dithiazole, respectively. The monomers were each reacted with pyromel litic dianhydride to synthesize the desired poly(amic acids). Films we re cast and cured to 350-degrees-C to effect imidization, producing fi lms with good mechanical properties. The copolymers exhibited good dim ensional (T(g) > 400-degrees-C) and thermal stability. Wide angle X-ra y diffraction measurements showed that in one case a semicrystalline m orphology was obtained producing a film with both a high modulus and l ow thermal expansion coefficient.