312 HIGH PERFORMANCE POLYMERS
13.5.5 Carbon Fiber Precursors
Poly(m-phenylene isophthalamide) (PMIA) and
other aramids have beenproposed as precursor for acti-
vated carbon materials [87]. These materials exhibit
a very homogeneous micropore size. This property
makes them usable as adsorbents, molecular sieves,
catalysts, or electrodes.
PMIA-derived carbon fibers can be activated by car-
bon vapor deposition of benzene. The activated carbon
fibers are suitableas molecularsieves forair separation
[88]. Carbon fibers can be obtained from the aramid
by pyrolysis at 750–850
◦
C. Which may take place in
Ar or CO
2
.
The fiber may be pre-impregnated with H
3
PO
4
.
Steam, CO
2
,andH
3
PO
4
serve as activators. The acti-
vation converts the amide groups in the polymer pre-
cursor ...