Preparation and study of new poly(phenylquinoxaline-ether-imide)s

New aromatic poly(phenylquinoxaline-ether-imide)s were synthesized by solution polycondensation reaction of aromatic diamines containing preformed phenylquinoxaline groups with two bis(ether-anhydride)s, namely 1,1-bis[p-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride or 1,1-bis[p-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride. All polymers were easily soluble in organic solvents, such as N-methylpyrrolidinone and dimethylacetamide, and even in less polar solvents like pyridine, tetrahydrofuran or chloroform, and gave flexible films by casting of such solutions. They showed high thermal stability, with an initial decomposition temperature above 300 degrees C and a glass transition temperature in the range of 220-271 degrees C. The polymer films exhibited good mechanical properties with tensile strength in the range of 38.5-78.2 MPa, elastic modulus in the range of 2.8-3.1 GPa and elongation to break in the range of 1.5-4.2%. The polymers showed weight- and number-average molecular weights in the range of 12000-23000 g/mol and 6000-11000 g/mol, respectively.