Thiele-Cohen swelling equation

Values for v obtained via equation (9) v v s determined from swelling the IPN s in toluene are shown in Figures 2 and 3 for the Thiele-Cohen equation and the modified Thiele-Cohen equation, respectively. While both equations fit the IPN data much better than the original Flory-Rehner equation, see Figure 1, the present modification fits somewhat better, on the average. 

If new physical or chemical crosslinks were added during IPN formation, one would expect the data to be shifted to the right of the theoretical line. Figure 3 indicates that substantially no new physical or chemical crosslinks are present, at least when the networks are fully swollen. However, analysis of the data does indicate that the contribution to the swelling by network I is out of proportion to its crosslink density and proportion in the IPN. The clearest indication of the conclusion can be found by examining the 4/1, 4/4, and 4/10 crosslink levels of the 44/56 composition samples investigated by Millar (15). Note that the experimental v s (x-axis) substantially do not vary in this series, while both the Thiele-Cohen (17) and modified Thiele-Cohen equations predict... 

Fig. 2. Swelling values predicted from the Thiele-Cohen equation experimental swelling values.

Fig. 3. Swelling values predicted by the modified Thiele-Cohen equation ye experimental swelling values.

J. L. Thiele and R. E. Cohen, Synthesis and Characterization of Single-Phase Interpenetrating Polymer Networks, Polym. Prepr. 19(1), 137 (1978). Swelling and modulus behavior Polystyrene/polystyrene IPNs. Swelling equation. 

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