Novel Thermooxidatively Stable Poly(ether-imide-benzoxazole) and Poly (ester-imide-benzoxazole)
Abstract
4-Hydroxy-5-nitrophthalimides were produced via nucleophilic aromatic substitution (NAS) of 4,5-dichloro phthalimide substituents by potassium nitrite. The use of a N-phenylphthalimide having a protected 4'-hydroxyl group allows concurrent deprotection and nitro reduction to amine to give the 4- hydroxy-5-amino-N-(4' hydroxyphenyl) phthalimide. This key intermediate Is the precursor to a poly(ether-imide-benzoxazole), and is the condensable monomer for a poly(ester-imide-benzoxazole). Benzoxazole monomer formation via condensation with p-fluorobenzoyl chloride afforded 2-(4'-fluorophenyl)-5,6,-N-(4'(- hydroxyphenyl)imide)benzoxazole, which was polymerized under NAS conditions to produce a poly(ether-imide-benzoxazole) having an endothermic transition at 454 deg C with weight retention of 90% at 500 deg C in both air and nitrogen. Solution polycondensation of the 4-hydroxy-5-amino-N-(4'-hydroxyphenyl) phthalimide monomer with isophthaloyl chloride afforded a poly(esteramide- imide) which was isolated and thermally cyclodehydrated in the solid state under vacuum to give a poly(ester-imide-benzoxazole) having 95% weight retention at 500 deg C in both air and nitrogen, with no detectable DSC transitions up to 500 deg C.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 15, 1994
- Accession Number
- ADA282381
Entities
People
- Lon J. Mathias
- Raj A. Sundar
Organizations
- University of Southern Mississippi