Title:
Phenomenological theory of the dynamics of polymer melts. II. Viscoelastic properties

Thumbnail Image
Author(s)
Skolnick, Jeffrey
Yaris, Robert
Authors
Advisor(s)
Advisor(s)
Editor(s)
Associated Organization(s)
Organizational Unit
Organizational Unit
Series
Supplementary to
Abstract
A phenomenological theory of the nonmechanical and viscoelastic properties of polymer melts is developed. Consistent with computer simulation results [A. Kolinski, J. Skolnick, and R. Yaris, J. Chem. Phys. 86, 1567, 7164, 7174 (1987)], that fail to find evidence for reptation as the dominant mechanism of long distance motion in a melt, we assume that the long-time behavior of a chain is that of a Rouse-like chain having a number of slow moving points, each with a friction constant proportional to the degree of polymerization n. Coupled with the assumption of rubber like behavior at short times made previously by Doi and Edwards [J. Chem. Soc., Faraday Trans. 2 74, 1802 (1978)], the theory predicts that over a broad molecular weight range the shear viscosity scales with n as approximately the 3.4 power of the molecular weight, and that ~n³ in the infinite molecular weight limit. Furthermore, the theory rationalizes the origin of the different crossover molecular weights for the shear viscosity and the self-diffusion coefficient, D. It also accounts for the origin of the intermediate time coupling of the center-of-mass motion into the internal coordinates and for the time dependence of the single bead positional autocorrelation functions seen in previous simulations. Proceeding by analogy to Graessley [J. Poly. Sci. Poly. Phys. Ed. 18, 27 (1980)], in the large molecular weight limit, phenomenological expressions for D and are derived and comparison is made with experiment.
Sponsor
Date Issued
1988-01-15
Extent
Resource Type
Text
Resource Subtype
Article
Rights Statement
Rights URI