THERMOSETTING POLYIMIDES - A REVIEW

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.