Abstract
In the present work, we report the results of an investigation of the
temperature and cross-link density dependences of the swelling activity
parameter S, or dilational modulus, which represents a difference in
free energy between the cross-linked and the uncross-linked systems, for
PDMS and polyisoprene within the framework of the Frenkel-Flory-Rehner
(FFR) theory. We find that the values of S (lambda(2) -> 1), where
lambda is the swelling stretch, are nonzero and increase as the
cross-linking density increases, implying that the Flory-Huggins
interaction parameters, which represents the energy contribution from
interspersing polymer and solvent molecules, of the cross-linked
(chi(c)) and uncross-linked (chi(u)) systems are different The full
analysis of S vs lambda(2)(s) within the FFR model also leads to the new
result that the difference between chi(c) and chi(u) decreases as the
degree of swelling increases. Results from torsional measurements for
network elasticity determination
Original language | English |
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Pages (from-to) | 2015-2022 |
Journal | Macromolecules |
State | Published - Mar 2013 |