Novel Poly(p-phenylene)s via Nucleophilic Aromatic Substitution of Poly(4‘-fluoro-2,5-benzophenone)

Abstract

Poly(4‘-fluoro-2,5-benzophenone) was synthesized by Ni(0) catalytic coupling and was reacted with various nucleophiles by aromatic substitution (SNAr) to produce substituted poly(p-phenylene) thermoplastics. Substitution by the nucleophiles was determined in most cases to be nearly quantitative by gel permeation chromatography, 1H NMR, and 19F NMR. The number-average molar masses of the derivatized polymers by gel permeation chromatography and multiangle laser light scattering ranged from 27.1 × 104 to 31.4 × 104 g/mol. The largest increase in the glass transition temperature, relative to that of poly(4‘-fluoro-2,5-benzophenone) was from 167 to 225 °C after displacement of fluoride by piperidine to give poly(4‘-piperidino-2,5-benzophenone). The storage modulus of poly(4‘-fluoro-2,5-benzophenone) was determined to be approximately 7.4 GPa at 50 °C by dynamic mechanical analysis, while the storage modulus of the improved film-forming 4-tert-butylphenoxy derivative (Tg = 170 °C) was 6.4 GPa at 50 °C.