Synthesis and characterization of new highly organosoluble poly(ether imide)s based on 3,3?,5,5?-tetramethyl-2,2-bis[4-(4-dicarboxyphenoxy)phenyl]propane dianhydride

A new bis(ether anhydride), 3,3′,5,5′-tetramethyl-2,2-bis[4-(4-dicarboxyphenoxy)phenyl]propane dianhydride (3), was prepared in three steps: the nitro displacement of 4-nitrophthalonitrile with 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, the alkaline hydrolysis of the intermediate bis(ether dinitrile), and the subsequent dehydration of the resulting bis(ether diacid). A series of new highly soluble poly(ether imide)s with tetramethyl and isopropylidene groups were prepared from the bis(ether anhydride) 3 with various diamines by a conventional two-stage synthesis including polyaddition and chemical cyclodehydration. The resulting poly(ether imide)s had inherent viscosities of 0.54–0.73 dL g−1. Gel permeation chromatography measurements revealed that the polymers had number-average and weight-average molecular weights of up to 54,000 and 124,000, respectively. All the polymers showed typical amorphous diffraction patterns. All of the poly(ether imide)s showed excellent solubility and were readily dissolved in various solvents such as N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, N,N-dimethylformamide, pyridine, cyclohexanone, tetrahydrofuran, and even chloroform. Most of the polymers could be dissolved with chloroform concentrations as high as 30 wt %. These polymers had glass-transition temperatures of 244–282 °C. Thermogravimetric analysis showed that all polymers were stable, with 10% weight losses recorded above 463 °C in nitrogen. These transparent, tough, and flexible polymer films were obtained through solution casting from N,N-dimethylacetamide solutions. These polymer films had tensile strengths of 81–102 MPa and tensile moduli of 1.8–2.0 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2556–2563, 2002