Ea. Gladkova et al., STABILITY OF SOLUTIONS OF AROMATIC POLYAMIDES CONTAINING CARBORANE UNITS IN THE MAIN-CHAIN, Macromolecular chemistry and physics, 196(2), 1995, pp. 593-598
The stability of aromatic polyamide chains containing 1,7-dicarba-clos
o-dodecaborane units was investigated in dilute solution by viscometry
and sedimentation analysis at 25 degrees C. Traces of impurities in d
imethylformamide bring about degradation of the polymer and formation
of polyanions, which become manifest in the viscosity by the polyelect
rolyte effect. Neutral salts suppress this effect. Degradation is not
hindered in an inert atmosphere. The solutions in N,N-dimethylacetamid
e and N-methyl-2-pyrrolidone are also unstable. No degradation occurs
in solutions in tetrahydrofuran stabilized with 2,6-di-tert-butyl-4-me
thylphenol. Hence, reliable measurements of the molecular characterist
ics of this polymer can be carried out only in stabilized peroxide-fre
e tetrahydrofuran.