Preparation and properties of soluble aromatic polyetherimides based on 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropan dianhydride

Aromatic polyetherimides were synthesized from a fluorine containing aromatic carboxylic acid dianhydride, 2,2-bis [4-(3,4-dicarboxyphenoxy)phenyl]-hexafluoropropane dianhydride (6F-BABPA) and five typical aromatic diamines including 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane (3F-DAM) by two-step procedures-amidation to polyamic acids (PAA), followed by thermal imidization of PAA. The chemical and physical properties of the newly prepared polyetherimides (PEI) were compared in terms of their chemical structures, inherent viscosities, mechanical, and thermal properties. All polyetherimides were well soluble in common organic solvents such as N-methyl-2-pyrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), pyridine, and methylene chloride. A PEI prepared from 6FBABPA/3F-DAM was especially easily dissolved in NMP. The glass transition temperature (T-g) range of the obtained PEI was 209-257 degrees C. The dielectric constants and refractive index were 2.8-3.2 and 1.61-1.56, respectively. The polyetherimide, 6F-BABPA/BAPP, with a low fluorine content (11.4% fluorine content), has 0.99% water absorption, whereas the polyetherimide, 6F-BABPA/4-BDAP, having a high fluorine content (26.0% fluorine content) showed 0.35% of water absorption. (C) 2000 John Wiley & Sons, Inc.