SYNTHESIS AND CHARACTERIZATION OF POLY(BENZOYL-1,4-PHENYLENE)S .2. CATALYST COLIGAND EFFECTS ON POLYMER PROPERTIES

High molecular weight, soluble poly(benzoyl-1,4-phenylene)s (eta(inh) = 0.99-1.6 dL/g) have been prepared by nickel-catalyzed polymerization of 2,5-dichlorobenzophenone in the presence of excess zinc and triphenylphosphine (PBP-A). Polymerization with 2,2'-bipyridine as coligand produces a soluble polymer (PBP-B) which exhibits a higher glass transition temperature of 217 degrees C (versus 149 degrees C for comparable PBP-A), a UV-vis lambda(max) at 352 nm (versus 328 nm for PBP-A), and only two C-13 NMR peaks in the carbonyl region at 196-198 ppm (versus an additional peak at 196.3 ppm for PBP-A). It has been proposed that these two polymers differ in the regiochemical placement of the lateral benzoyl groups along the chain, with PBP-B exhibiting more regular head-to-tail structures. These soluble polymers show no evidence for crystallinity by DSC or by WAXD and exhibit high thermal stability (only 3% weight loss in air or N-2 on heating to 500 degrees C). Film samples show tensile moduli of 6.4 GPa and tensile breaking strengths in the range of 0.9 Gpa.