In this work, potential problems with the application of polymer matrix composites
(PMC) in extreme environments [1] is discussed. Then, two specific examples of the applications of
PMCs in high voltage [2-7] and high temperature [8-15] situations are evaluated. The first example
deals with damage evolution in high voltage composite insulators [2-7] with PMC rods subjected to
a combined action of extreme mechanical, electrical and environmental stresses. These insulators
are widely used in transmission line and substation applications around the world. Subsequently,
advanced high temperature graphite/polyimide composites [8-15] are evaluated for aerospace
applications. The composite investigated in this project were used to manufacture and successfully
test a Rocket Based Combined Cycle (RBCC) third-generation, reusable liquid propellant rocket
engine, which is one possible engine for a future single-stage-to-orbit vehicle [8].
