
15: POLY(IMIDE)S 349
curing. In the same way, nadic anhydride can be used
as a reactive modifier [46].
Materials built up according to this concept exhibit
low melt viscosities. They are stable for several hours
at 210–275
◦
C. The thermal curing of the phenyl-
ethynyl group does not occur to any appreciable extent
at temperatures below 300
◦
C. Thermal curing takes
place from 300 to 350
◦
C. The phenylethynyl groups
react to provide a crosslinked resin system [47].
Phenylethynyl-terminated imide (PETI) monomers
can be used as reactive diluents for melt process-
able PETI oligomers [11]. Melting points of such
monomers are shown in Table 15.4.
The viscosities