Dilute solution and rheological characterization of branched poly(2,2′‐oxydiethylene trans ‐1,4‐cyclohexanedicarboxylate)

The addition of small amounts of polyfunctional agents can substantially alter the melt and the solid‐state properties of polymers. A practical characterization scheme is necessary for control of polymer preparation and for process analysis. Trifunctionally branched samples of poly(2,2′‐oxydiethylene trans ‐1,4‐cyclohexanedicarboxylate) have been prepared as representative of polycondensation polymers. The Drott‐Mendelson procedure was applied to the dilute solution data from gel permeation chromatography and intrinsic viscosity to yield the true molecular weight distributions and the average branching frequency. The melt zero‐shear‐rate viscosity of a branched sample was less than that of a linear sample of equal weight‐average molecular weight, in good agreement with Bueche's theory. The melt elasticity, as measured by the terminal relaxation time, was equal to that of the equivalent linear polymer at constant weight‐average molecular weight.