TY - JOUR
T1 - Thermodynamics of rubber elasticity
JF - Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
JO - Proc R Soc Lond A Math Phys Sci
SP - 331
LP - 350
M3 - 10.1098/rspa.1976.0145
VL - 351
IS - 1666
AU -
Y1 - 1976/11/19
UR - http://rspa.royalsocietypublishing.org/content/351/1666/331.abstract
N2 - The process of vulcanization, which links the polymer molecules into a three dimensional network, enables reversible thermodynamic measurements to be made on elastomeric materials from which the entropy and energy contributions to the free energy of deformation can be determined. The molecular processes responsible for rubber elasticity are most readily interpreted in terms of the constant volume coefficients (∂U/∂L)V, T and (∂S/∂L)V, T. Taken as a whole the results from thermodynamic studies on lightly cross-linked rubbery polymers support the view that the retractive force is primarily intramolecular in origin. The results also show that in general the retractive force contains a significant energetic contribution. The Gaussian theory of rubber elasticity as reformulated by Flory is able to account satisfactorily for the temperature dependence of the force, but it does not lead to an adequate representation of the pressure dependence of the force and hence of the strain induced dilation. Several phenomenological equations which have been proposed for predicting the dilation behaviour for the case of simple extension are considered.
ER -