Interpenetrating polymer networks with controllable intermolecular hydrogen bonding: Swelling behavior

Summary

The swelling behavior in different solvents of IPNs based on poly(butyl acrylate) and modified polystyrene containing strong proton-donor hydroxyl groups is studied. The experimental data of the volume fractions of the networks in the swollen state V_expt at equilibrium are compared with those expected from the Thiele-Cohen equation (V_TC), which assumes that the two networks are independent and no additional crosslinks form during the formation of the IPNs. For the IPNs without inter-component hydrogen bonding, V_expt in toluene are in good agreement with V_TC. As the hydroxyl content increases, the deviation of V_expt from V_TC increases indicating more crosslinks form in the process of IPN formation. This deviation in the solvents of proton-acceptor type becomes smaller but still apparent. This result implies that hydrogen bonding between the components is destroyed by the solvents but the physical entanglements formed during the formation of the IPNs remain.