VISCOSITY CHARACTERIZATION OF AN ALTERNATING COPOLYMER OF ETHYLENE AND TETRAFLUOROETHYLENE

Viscosity measurements on dilute solutions of an alternating copolymer of ethylene and tetrafluoroethylene (PETFE) in diisobutyl adipate have been performed at 240 °C. [η] = 2.3 X 10-3 Mw0.71 (mL/g) with Mw expressed in grams per mole, in fairly good agreement with the result based on the diffusion exponent αD = 0.58 in which αη = 3αD - 1 ≈ 0.74. When the solvent viscosity is combined with previous laser light scattering characterizations of the same polymer solutions, the hydrodynamic radius (Rh) and the ratio of Rh/Rg can be computed where Rg is the radius of gyration. As Rh/Rg = 1.29, 0.663, and ~0.54 for a hard sphere, a Gaussian coil, and an expanded coil, respectively, a value of ~0.58 suggests that the PETFE copolymer in diisobutyl adipate at 240 °C forms slightly expanded coils as in a fairly good solvent. © 1990, American Chemical Society. All rights reserved.