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Stored energy of cold work in polystyrene
Author(s) -
Chang Benjamin TaiAn,
Li J. C. M.
Publication year - 1988
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.760281810
Subject(s) - materials science , differential scanning calorimetry , polystyrene , composite material , expanded polystyrene , stored energy , saturation (graph theory) , activation energy , work (physics) , compression (physics) , thermodynamics , metallurgy , polymer , chemistry , physics , mathematics , combinatorics
The energy stored in polystyrene after plastic deformation is measured by the differential scanning calorimetry (DSC) technique. Similar to metals, the stored energy increases with plastic straining, first rapidly, and then more slowly, and finally the stored energy seems to approach a saturation value (about 1 cal/gram). By comparing to the plastic work done, the fraction stored ranges from 30 percent after 10 percent compression to 10 percent after 60 percent compression. The fraction is about twice as large as that of copper. The release of stored energy has two distinct parts, one below T g and the other above T g . Most of the strain recovery seems to accompany the second part. By using the Kissinger plot, the second part has an activation energy, of 142 kcal/mole which is about 10 percent larger than that of compressive strain recovery.