Gm. Mikhailov et al., CHEMICAL-STRUCTURE, MORPHOLOGY, AND PROPERTIES OF MODIFIED-POLYPYROMELLITIMIDE FIBERS, Russian journal of applied chemistry, 67(12), 1994, pp. 1773-1778
Fiber-forming polypyromellitimide has been modified by incorporation o
f rigid p-bis(aminophenyl)pyrimidine units into the main polymer chain
. The structures of copolyimide fibers obtained have been studied by x
-ray diffraction and electron microscopy.