Quasichemical approach to crosslinked polymer solutions and the swelling equation for polycondensation networks

Abstract

The change of free enthalpy and the chemical potential of solvent for mixing of solvent with crosslinked structures formed by stepwise reactions of the polycondensation type has been derived by an adaptation of the quasichemical equilibrium method. Each monomer unit is supposed to bear a different number of crosslinkable contact points, the coupling of which gives rise to chemical bonds, and of uncrosslinkable contact points, involved in interactions with the solvent, which may be of different type. The results are used to analyze the effect of network topology on the parameters of the swelling equation, particularly on a parameter characterizing the network composition. This parameter may be obtained from analytical data or by using the crosslinking statistics; and model calculations show how it varies with monomer conversion.