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Thermodynamic behavior of solid polymers in uniaxial deformation
Author(s) -
Lyon R. E.,
Farris R. J.
Publication year - 1984
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.760241110
Subject(s) - materials science , deformation (meteorology) , elastomer , work (physics) , internal energy , composite material , polyethylene , polymer , strain energy density function , low density polyethylene , crystallization , thermodynamics , physics , finite element method
The heat and work of uniaxial deformation were measured for two commercial polyurethane elastomers and a low density polyethylene using a new deformation calorimeter. Internal energy changes in the materials resulting from deformation were calculated from the difference between the heat and work according to the first law of thermodynamics. The elastomers were found to exhibit complete reversibility for small and large strain deformation cycles as determined from the absence of a permanent internal energy change, even though one of these undergoes strain‐induced crystallization and melting. The low density polyethylene behaves irreversibly even at small strains, and will store 30 percent of the deformation work as internal energy during drawing at room temperature.