This paper reviews the chemistry, properties, and applications of PMR
polyimides, acetylene-terminated polyimides and bismaleimides. Thermos
etting polyimides are being developed for use as matrix resins in stru
cturally efficient advanced composites for aerospace and future non-ae
rospace applications. Their chemical structures can be altered to enha
nce toughness, processing ease, and temperature performance. However,
it is very difficult to attain these three desired properties in one p
roduct. Bismaleimides are popular for use in the temperature range of
150-250 degrees C because of their epoxy-like processing and polyimide
-like temperature capability. PMR polyimides are suitable for temperat
ures up to 371 degrees C because of their outstanding thermo-oxidative
stability, Acetylene-terminated Thermid materials are less favored be
cause of the difficulty in processing; however, improvements in the pr
ocessability are emerging.