Soluble High-Tg Polyetherimides with Good Flame Retardancy Based on an Asymmetric Phosphinated Etherdiamine

This study focuses on preparing soluble, high-T-g polyetherimides (PEls) with good flame retardancy. To achieve this goal, a phosphinated aminophenol, 1-(4-hydroxypheny1)-1-(4-aminopheny1)-1-(6-oxido-6H-dibenz < c,e >< 1,2 > oxaphosphorin- 6-yl)ethane (1), was prepared. Then, an asymmetric etherdiamine, 1-(4-(4-arninophenoxy)phenyl)-1-(4-aminophenyl)-1-(6-oxido-6H-dibenz < c,e >< 1,2 > oxaphosphorin-6-yl)ethane (3), was prepared from the nucleophilic substitution of (1) with 4chloronitrobenzene, followed by catalytic hydrogenation. Light colored, tough, and foldable PEls (5) with good thermal stability, organo-solubility, and good flame retardancy were synthesized from the condensation of (3) with various aromatic dianhydrides in N,N-dimethylacetamide, followed by thermal imidization. Properties of the resulting PEls were evaluated and compared with those of symmetric PEls (5') and polyimides (5 ''). The structure-property relationships were discussed. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1331-1340, 2011