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Molecular weight distribution and rheological properties of polyisobutylene solutions
Author(s) -
Nishida Noboru,
Salladay David G.,
White James L.
Publication year - 1971
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1971.070150513
Subject(s) - gel permeation chromatography , molar mass distribution , rheology , polymer , permeation , viscosity , polymer chemistry , materials science , chemistry , thermodynamics , molecular mass , composite material , organic chemistry , membrane , enzyme , biochemistry , physics
The molecular weight distribution of a series of polyisobutylenes was determined using osmotic pressure measurements, gel permeation chromatography, and intrinsic viscosity. All of the polymers except for one, a blend of the highest and lowest molecular weight constituents, had similar moderate molecular weight distributions. The “extended chain length” method of calibrating the gel permeation chromatograph for polyisobutylenes was found to be effective. Steady state and transient shear stresses and normal stresses were measured on 5% decalin solutions of these polymers. The zero shear viscosity increased with the 3.3 power of molecular weight, and the zero shear normal stress coefficient (σ 11 − σ 22 )/Γ 2 varied with the 7.5 power. Relative elastic memory as measured by (σ 11 − σ 22 )/σ 12 or stress relaxation increased with increasing molecular weight (and at constant number‐ or weight‐average molecular weight) with breadth of distribution. Stress overshoot also correlated with this tendency.