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A viscosity–molecular weight relationship for polydimethylsiloxanes
Author(s) -
Takimoto H. H.,
Forbes C. T.,
Laudenslager R. K.
Publication year - 1961
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.1961.070051404
Subject(s) - polydimethylsiloxane , intrinsic viscosity , viscosity , molar mass distribution , polymer , toluene , light scattering , chemistry , thermodynamics , polymer chemistry , materials science , organic chemistry , scattering , optics , physics
The relationship of intrinsic viscosity [η] to the weight‐average molecular weight M̄ w of polydimethylsiloxane in toluene at 25°C. has been determined. The modified Staudinger equation, [η] = K M̄ w a , with K = 2.43 × 10 −5 and a = 0.84, describes the relationship for the above polymers in the range of weight‐average molecular weight from 18,900 to 124,500 (as determined by light‐scattering measurements). These constants differ from the values reported by Barry, where K = 2 × 10 −4 and a = 0.66 were obtained. The difference is attributed to the fact that Barry dealt with number‐average rather than weight‐average molecular weight.