where, m = cross-link density; v1 = polymer–solvent interaction parameter; Vs = molar volume of solvent; Vr = volume fraction of rubber in the swollen gel; Vr was calculated using the relation
where, m = cross-link density; v1 = polymer–solvent interactionparameter; Vs = molar volume of solvent; Vr = volume fraction ofrubber in the swollen gel; Vr was calculated using the relation