Adjusting the measured weight loss of aged graphite fabric/PMR-15 composites

The purposes of this study is to evaluate the gr growth of the surface dama ge layer in polymer matrix composites (PMC's) fabricated with graphite fabr ic reinforcement and to determine the effects of the cut-surface degradatio n on the overall thermo-oxidative (TOS) stability of these materials. Four important conclusions were made about the TOS behavior of T650-35/PMR-15 fa bric-reinforced composites: 1) Three stages of composite weight loss were s een on the plot of weight loss versus aging rime; 2) the depth of the cut-e dge damage is related to the composite thickness, 3) the actual weight loss realized by a mechanical test specimen that has had all the aging-induced cut-edge damage removed during the preparation process is significantly les s than the weight loss measured using specimens with a high percentage of c ut edges exposed to the damaging environment, and 4) an extrapolation of a section of the weight loss curve can be used to obtain a move correct estim ate of the actual weight loss after extended periods of aging at elevated t emperatures.