SYNTHESIS AND CHARACTERIZATION OF XY-(2,5-DIBENZOYL-1,4-PHENYLENEOXY)-1,4-PHENYLENE]

y-(2,5-dibenzoyl-1,4-phenyleneoxy)-1,4-phenylenel] (3) was prepared by the aromatic nucleophilic substitution reaction of 2,5-difluoro-4-ben zoylbenzophenone (2) with hydroquinone (1) in the presence of potassiu m carbonate in diphenylsulfone. The polycondensation was conducted at 150-320 degrees C for 4 h and produced polymer 3 at excellent yield le vels. Polymer 3 was characterized by elemental analysis, i.r. spectros copy, differential scanning calorimetry (d.s.c.) and wide angle X-ray measurement (WAXD). Polymer 3 showed two endothermic peaks on d.s.c. s cans, which would be attributable to recrystallization effects; the lo wer-temperature endotherm represented only a portion of the melting en dotherm of original crystals and the upper-temperature endotherm was t he melting of crystals reorganized during a heating scan. (C) 1997 Els evier Science Ltd.