Miscibility and Immiscibility of IPNs

The calculations were done for IPNs based on PU and styrene-DVB copolymer. 

Calculations have shown that in almost all cases the values of AHi,2 are positive. It is known that positive values of the enthalpy of mixing show that such a pair is thermodynamically incompatible. Thus, in spite of forming the monolithic system, two constituent networks are not compatible, and formation of IPNs as a whole is the result of synthesis in the regime of forced compatibility. Only in the regions where the amount of one of the network 

From experimental data on benzene vapor sorption by all polymer systems, the changes in partial free energy of benzene by sorption (dissolution) may be found as 

Afi2 for the polymer components has been calculated according to the Gibbs-Duhem equation. 

The average free energy of mixing of solvent with the individual components, with IPNs of various compositions, and with gradient IPN layer for solutions of different concentrations was estimated according to the equation  

---