Theta temperature Polybutadiene

Problem 3.25 For a fractionated sample of cis-1,4-polybutadiene of molecular weight 123x10 intrinsic viscosities were measured [30] in three different solvents at respective theta temperatures. From the results given below determine the variation of the unperturbed dimensions of the polymer molecule with temperature. [Pg.217]

The critical temperature %) at which the solutions of cis-1,4-polybutadiene in n-heptane underwent separation into two phases were measured for three carefully fractionated polymer samples having different molecular weights (M). From the data, given below, determine the theta temperature (0) for the polymer in n-heptane. [Pg.225]

Viscosity measurements were made on solutions of fractionated cis-1,4-polybutadiene samples in toluene at 30°C and in n-heptane at —1°C (theta temperature), yielding the following values of intrinsic viscosities (in dL/g) ... [Pg.226]

We first consider the behavior of the dynamic storage modulus and the dynamic loss modulus. Colby, et a/. (15) report an extremely extensive series of measurements of the storage and loss moduli of a 925 kDa (M ) polybutadiene having a narrow molecular weight distribution (M /Mn < 1.1 M /Mw < 1-1). Solutions were made in the Theta solvent dioctylphthalate (DOP) at 12°C above the Theta temperature, and the good solvent phenyloctane (PO). Viscosities were reported at 15 volume fractions extending from extreme dilution 0.001) up to the melt full... [Pg.403]

Big Chemical Encyclopedia