Actions for Structure-to-property relationships in addition cured polymers. 4 : Correlations between thermo-oxidative weight losses of norbornenyl cured polyimide resins and their composites
Structure-to-property relationships in addition cured polymers. 4 : Correlations between thermo-oxidative weight losses of norbornenyl cured polyimide resins and their composites
Relationships are identified between the thermo-oxidative stability (TOS) at 316 C of a wide variety of PMR (polymerization of monomeric reactants) addition cured polyimide resins and their corresponding graphite fiber composites. Weight loss results at 316 C confirmed the expected relationship of increasing aliphatic endcap content with decreasing TOS. Moreover, the resin TOS study also showed an unexpected linear correlation of decreasing weight loss to increasing ratio of benzylic diamine to aliphatic endcap in the range of the stoichiometries studied. Only after long term 316 C aging does the dianhydride used with the benzylic diamines become an additional factor in influencing the amount of PMR resin and composite weight losses. Also, the benzylic systems consistently showed much lower resin and composite weight losses at 316 C than the corresponding nonbenzylic norbornenyl resins and composites, except when the nonbenzylic diamine monomer does not contain a connecting group. Instead, this diamine resulted in a 316 C resin and composite weight loss that was only competitive with benzylic type diamines. Results show excellent correlation between TOS of all graphite fiber PMR composites and resins.
Document ID: 19920010797. Accession ID: 92N20039. AVSCOM-TR-92-C-002. NAS 1.15:105553. AD-A253050. E-6876. NASA-TM-105553. National Meeting of the American Chemical Society, Symposium on Advances in Polymer Matrix Composites; 5-10 Apr. 1992; San Francisco, CA; United States.