Xd. Hu et al., A tetramethylbiphenyl poly(benzobisthiazole): Synthesis, chracterization, fiber spinning, and properties, MACROMOLEC, 33(9), 2000, pp. 3342-3348
Poly(benzobisthiazole)s containing an o-tetramethyl substituted biphenyl mo
iety were synthesized based on 2,S-diamino-l,4-benzenedithiol dihydrochlori
de and 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarbonyl chloride. Homopolymeri
zation of the two monomers and copolycondensation of the two monomers with
terephthaloyl chloride were carried out in poly(phosphoric acid) (PPA). The
interfacial polymerization technique was used to enhance the formation of
a homogeneous liquid crystalline polymer solution suitable for fiber spinni
ng. Copolymers of tetramethylbiphenyl PBZT/PBZT (25/75) were successfully s
pun into fibers from liquid crystalline solutions in PPA. Fibers were therm
ally cross-linked between 500 and 550 degrees C. The thermal cross-linking
reaction was studied by thermogravimeteric analysis and by C-13 solid-state
NMR spectroscopy. Fiber morphology and properties are also reported and di
scussed.