
5: POLY(PHENYLENE SULFIDE) 137
S
S
F
F
Figure 5.8 2,7-Difluorothianthrene.
Thianthrene-based poly(phenylene sulfide)s can be
prepared from 2,7-difluorothianthrene and dithiols,
including 4,4
-thiobisbenzenethiol, m-benzenedithiol,
or sodium sulfide nonahydrate [57]. Aromatic nucle-
ophilic substitution reactions are employed.
The thus-prepared materials exhibit excellent ther-
mal stability, e.g., glass transition temperatures of
143–147
◦
C and only 5% weight-loss at tempera-
tures above 430
◦
C. Very high refractive indices up
to 1.8020 are observed along with a high transparency
in the visible region and a low birefringence in the
range of 0.0037–0.0039 [57].
5.2.12 ...