Synthesis of Fusible Branched Polyphenylenes

Abstract

Fusible polyphenylenes with molecular weights approaching 3000 have been prepared by the cationic oxidative polymerization of m-terphenyl, o-terphenyl,1,3,5-triphenylbenzene, or mixtures of the terphenyls with biphenyl and with benzene. Polymerizations were carried out in the molten state with either aluminum chloride catalyst and cupric chloride as oxidizer or the much less efficient ferric chloride, which served both functions. Fusible polymer fractions were isolated by a series of continuous extractions with hot aromatic solvents. Polymers in the 2000-to-3000 molecular-weight range generally melted between 300 and 400°C. The polymer chains are presumed to have phenyl branches besides some fused ring structures, evidence of the latter being their carbon-to-hydrogen ratios of up to 1.67.