Monomers of poly(aryl ether ketone)s family, such as, 4,4'-hydroquinon
e (PD), 4,4'-biphenol(S-3) and 4,4'-difluorine benzophenone have been
researched by uh initio RHF method. Results obtained show that these m
onomers have different torques in their aromatic rings. S-3 has a dihe
dral angle of 51.8 degrees, its reactivity is a bit stronger than that
of PD, but it introduced more active branching points. Thus, polymer
DPEEK from S-3 has more serious chain branching and is more difficult
in crystallizing than PEEK from PD. And also, it is found that there i
s a kind of red negative ion in DPEEK solution of concentrated H2SO4.