Aging of Interpenetrating Polymer Networks

Design and Applications of Dynamic Hydrogels Based on Reversible C═N Bonds

“…When a system has more than one network and the same crosslink type occurs only between the same polymer backbones, the network topology will potentially become a so‐called interpenetrating polymer network (IPN) ( Figure a). According to the definition of the IUPAC compendium of chemical terminology, an IPN is “A polymer comprising two or more networks that are at least partially interlaced on a molecular scale but not covalently bonded to each other and cannot be separated unless chemical bonds are broken.” [ 51 ] IPNs are combinations of polymer networks, at least one of which is synthesized or crosslinked in the presence of the other, [ 52 ] it is not a simple blending of two or more preformed networks. If there are un‐crosslinked linear or branched macromolecules that are dispersed in the IPN and that can be separated from the network without breaking chemical bonds, then this topology is called a semi‐IPN.…”

“…[ 54 ] For homo‐IPNs, the phase separation can be almost completely avoided and a full interpenetrating of polymer chains is obtained since the networks are thermodynamically miscible. [ 52 ] Compared with SCNs and DCNs, a synergistic effect of all components is observed in IPNs, [ 55 ] which often exhibit improved mechanical properties over single network hydrogels. [ 56 ] In addition, IPNs have shown advantages in terms of thermal stability, chemical resistance, and suppression of creep and flow of the hydrogels.…”