Light Scattering Investigation of the Structure of Polystyrene

Abstract

Using light scattering, the mean square molecular radius and length of a number of samples of polystyrene have been measured as a function of solvent and temperature. Molecular weights, intrinsic viscosities, and ``osmotic second virial coefficients'' have also been determined on many of the samples. From the data it may be concluded: (1) that polystyrene molecules are extended and stiffened by steric interactions of the phenyl groups; (2) that the molecules are largely unbranched; (3) that the heat of dilution is negative in some solvents, contrary to the usual situation in hydrocarbon systems; (4) that the osmotic second virial coefficient depends strikingly on molecular weight for a given solvent; (5) that there is a good correlation between this coefficient and the mean square radius at a given molecular weight; (6) that the intrinsic viscosity is strictly proportional to a power of the molecular weight over the molecular weight range from 2,000 to 2,000,000, but that deviations occur at lower molecular weights; (7) that the intrinsic viscosity and mean square radius are functions of solvent at high molecular weights but not at very low molecular weights. Theoretical concepts necessitated by these observations are discussed briefly.

Flory Enthalpy Parameter at Infinite Dilution of Polymer Solutions Determined by Various Methods

“…(LS), 17 Krigbaum and Carpenter (LS), 6 Schulz and Baumann (LS), 18 Kotera et al (LS), 19 Miyaki-Fujita (LS), 20 The value of 0 for the samples in Krigbaum's study, except sample code H-2-8, is 305.6±0.4K, which is somewhat lower than those estimated by others for this system. Krigbaum 3 ascribed this disagreement to traces of moisture which entered the polymer solutions in the 313.2 K bath.…”

The Solution Behavior of Polystyrene Derivatives: Poly-p-methoxystyrene

“…The dependence of the root mean square endto-end distance on the molecular weight is expressed by: (2) a constant as determined from a plot of log(<D2>z1/2) against log Mw, and the relations for poly p-methoxystyrene are:…”

When Polymer Science Looked Easy

“…With this taken into account, everything fell into place; three independent methods of calibrating the photometer agreed, and the measured scattering from pure liquids and from solutions of simple substances was in accordance with theory (83). Using this methodology, Paul Outer, a post-doctoral fellow from Belgium, was able to make an extensive series of measurements on polystyrene solutions and to get all the numbers well pinned down (84).…”