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Calculation of relaxation time in polyurethanes using additive group contributions
Author(s) -
Hartmann Bruce,
Lee Gilbert F.,
Lee John D.,
Fedderly Jeffry J.,
Berger Alan E.
Publication year - 1996
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/(sici)1097-4628(19960613)60:11<1985::aid-app23>3.0.co;2-z
Subject(s) - glass transition , relaxation (psychology) , thermodynamics , logarithm , materials science , polymer , atmospheric temperature range , polymer chemistry , chemistry , physics , mathematics , composite material , psychology , social psychology , mathematical analysis
The method of additive properties was used to calculate the dynamic mechanical relaxation time for a series of polyurethanes. Calculations were also made of density and glass transition temperature. Group contributions for nine component groups were determined. With these group values, the densities of the 12 polymers used to determine the groups were calculated and found to agree with measured values within an average of 0.2%. Calculated glass transition temperatures also agreed with measured values within 0.2%. The relaxation time, defined as a parameter in the Havriliak‐Negami equation, was shown to be correlated with the glass transition temperature, allowing relaxation time to also be expressed as an additive property. Calculated logarithms of relaxation times agree with measured values to within 7% over a range of relaxation times covering many decades. © 1996 John Wiley & Sons, Inc.