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Internal pressure behavior of polymers above and below the glass temperature
Author(s) -
Bagley E. B.,
Scigliano J. M.
Publication year - 1971
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760110409
Subject(s) - materials science , polymer , brittleness , internal energy , glass transition , composite material , internal pressure , molding (decorative) , volume (thermodynamics) , cracking , solvent , thermodynamics , organic chemistry , chemistry , physics
It has been well established in the literature that the internal pressure, P i = (∂ E/∂V ) T , of a polymer in the glassy state is about half the value expected from the behavior of the polymer just above the glass temperature, Tg . Consideration of this behavior in terms of a recent analysis of factors affecting internal pressures leads to the conclusion that the expression for the total energy of a glass must include a volume‐dependent stored energy term, a term not present above Tg . This stored energy could be associated with actual bond and segment deformations in the glassy state. Brittleness and solvent cracking behavior of glasses will be strongly dependent on this stored elastic energy which can be modified by altering the molding conditions under which the glass is formed.