Poly(2,6‐diphenyl‐1,4‐phenyl oxide): Characterization by gel‐permeation chromatography, light scattering, and solution viscosity

Abstract

AbstractTen unfractionated poly(2,6‐diphenyl‐1,4‐phenylene oxide) samples were examined by gel permeation chromatography (GPC) and intrinsic viscosity [η] at 50°C in benzene, by intrinsic viscosity at 25°C in chloroform, and by light scattering at 30°C in chloroform. The GPC column was calibrated with ten narrow‐distribution polystyrenes and styrene monomer to yield a “universal” relation of log ([η]M) versus elution volume. GPC‐average molecular weights, defined as M̄gpc = \documentclass{article}\pagestyle{empty}\begin{document}$\Sigma w_i [\eta ]_i M_i /\Sigma w_i [\eta ]_i$\end{document}, wi denoting the weight fraction of polymer of molecular weight Mi, were computed from the GPC and [η] data on the polyethers. The M̄GPC were then compared with the weight‐average M̄w from light scattering. The intrinsic viscosity (dl/g) versus molecular weight relations for the unfractionated poly(2,6‐diphenyl‐1,4‐phenylene oxides) determined over the molecular weight range 14,000 ≤ M̄w ≤ 1,145,000 are log [η] = −3.494 + 0.609 log M̄w (chloroform, 25°C) and log [η] = −3.705 + 0.638 log M̄w (benzene, 50°C). The M̄w(GPC)/M̄n(GPC) ratios for the polymers in the molecular weight range 14,000 ≤ M̄w ≤ 123,000 approximate 1.5 according to computer integrations of the GPC curves with the use of the “universal” calibration and the measured log [η] versus log M̄w relation. The higher molecular weight polymers (326,000 ≤ M̄w ≤ 1,145,000) show slightly broadened distributions.