Poly(fluoroalkoxyphosphazene) Lip Seal Materials.

摘要

The objective of this program was to develop poly(fluoroalkoxyphosphazene) terpolymer compounds suitable for lip seal applications over a temperature range of -70F to 250F with a projected lifetime of 1000 hours or more. Compounding studies with (CF3CH2O)2PN-(HCF2C3F6CH2O)2PN)n terpolymers indicate the objective can be met. Candidate seal compounds were developed that had good original stress-strain properties and retained these properties after aging at 350F in air for up to 500 hours. The ((CF3CH2O)2PN-(HCF2C3F6CH2O)2PN)n terpolymer lip seal compounds exhibited low volume swell and weight change in the ASTM test fuels at 73F and good hydrolytical stability at 212F and 100% relative humidity. Low temperature compression set tests at -70F and Gehman test results indicate these compounds will be serviceable at -70F. Material evaluation tests have not been correlated to actual service life; therefore the ((CF3CH2O)2PN-(HCF2C3F6CH2O)2PN)n terpolymer compounds developed on this program should undergo hynamic testing to complete qualifications.