AN EVALUATION OF NEW AND POTENTIALLY HEAT RESISTANT GLASS REINFORCED PLASTICS.
Final rept. 1 Jun 65-30 Sep 66,
BRUNSWICK CORP MARION VA DEFENSE DIV
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Significantly, vacuum bagging at low temp. 350 F followed by postcure to 600 F yielded the best results for PI polyimide composites, although their void content could not be reduced to below 16-18. DPO diphenyl oxide press cured laminates and vacuum bagged FW filament wound composites required extensive postcure cycles one week to 550 F. Average room temp. flexural strength and modulus of PI laminates was 75,000 psi and 2.9 10 to the 6th power psi and 77,000 psi and 3.9 10 to the 6th power psi for DPO. A finish evaluation study showed no substantial improvement in elevated temp. resistance of either DPO or PI composites. Based on the data generated, the useful life of PI composites is well beyond 1000 hrs. at 500 F but much shorter at 600 F with very little strength retention at 700 F. Based on the data generated, DPO composites should have a useful service life beyond 1000 hrs. at 400 F and 500 F with some strength retention up to 250 hrs. at 600 F. DPO composite strengths at 400 F and PI composite strengths at 500 F are virtually level straight-line functions.
- Laminates and Composite Materials