High-service temperature polyether amide thermoset resins-new materials for electrical insulation and high strength composites

摘要

The copolymerization of bisoxazolines and thermoplastic phenolic novolaks results in a family of polyether amide (PEAR/sup TM/) thermoset resins that are finding applications in a variety of demanding fields, such as aerospace composites, oil service, and selective high temperature industrial and automotive areas. The key properties of all grades of PEAR resin include: excellent adhesion to a variety of fibers, substrates and fillers; very high heat resin modulus; high compression and shear strength; excellent composite hot-wet properties; high resistance to thermo-oxidation at elevated temperatures; outstanding toughness; low exotherm during cure; low flammability and low smoke release; low coefficient of linear thermal expansion; low shrinkage during cure; and zero volatiles release. PEAR precursor-catalyst mixtures and prepregs have long term stability at room temperature and may be cured in about an hour at 177/spl deg/C followed by post-cure at 225/spl deg/C. PEAR electrical properties vary with formulations, but in general meet or exceed epoxies at room and elevated temperatures. Potential electrical applications include high voltage insulators, printed circuit boards, cast resin dry type transformers for Class H+ service, resin-rich prepreg mica tapes for motor and generator coils and prepregs for step press molding of continuous lengths of parts used in many insulation applications.