Synthesis of novel polyimides for the testing of structure-processing and property relations when used to form high temperature polymer matrices

摘要

High-performance polymers have found an extreme range of applications in theaerospace industry. Composites which have polymers incorporated in them can usuallymeet the needs of the design, and are the ideal materials for aerospace applications dueto their light weight, high strength, and radar transparency. Phenyl-ethynyl terminatedoligomers, for example, have found many uses in the aerospace industry. Phenyl-ethynylterminated oligomers (AFR-PEPA-N) exhibit glass-transition temperatures of up to450????C. Unfortunately crystals form due to interactions of the oligomers. These crystalsdo not melt until 360????C after 15 minutes when the resin is already 50% cured.Investigation was performed to find any possible alteration to the end-caps andmonomer chain elements of the current AFR-PEPA-N. Several siloxane related amineswere added to the AFR-PEPA-N chain to form protective coatings when in service athigh temperatures. The new poly(siloxane imide) showed an increase in processabilitywhile mantaining AFR-PEPA-N properties. In addition, phenyl-ethnyl end-caps weresubstituted with an ethynyl end-caps which showed no improvement in processability.