Experimental Tests of Entanglement Models of Rubber Elasticity. 2. Swelling

Experimental swelling data are used to compare theoretical models of rubber elasticity. Of the nine models that were examined, only the Gaylord and Marrucci tube models, the modified Graessley primitive path model, and the Flory-Erman constrained junction fluctuation model provide even qualitative agreement with the observed network behavior. Quantitative agreement is impossible for the Flory-Erman model and requires physically unrealistic parameter values for the other three models. The assumed separability of elastic and mixing free energy terms remains questionable.