Concentration dependence of solution viscosities of rigid rod polymers

A series of poly(benzoyl-1,4-phenylene)s (PBP), with different molecular weights and microstructures that are soluble in organic solvents, was synthesized. By using different catalysts, PBP-II which contains both head-to-tail and head-to-head linkages, and PBP-I in which the repeating units are arranged predominantly in a head-to-tail fashion were synthesized. The intrinsic viscosity of PBP-I in dimethylacetamide is 0.57 dL/g, and the GPC (gel permeation chromatography) molecular weight is 2.65×104. The ratio of Mw/Mn from GPC data is 1.7 for PBP-II and 2.5 for PBP-I.