Interpenetrating Polymer Networks: Processing, Properties and Applications

Interpenetrating polymer networks (IPNs) are defined as combination of two or more polymers in network form with at least one of which is polymerised and/or crosslinked in the immediate presence of the others. IPNs are based on combinations of two or more polymers and are younger cousins to polymer blends, blocks and grafts. All these are members of a larger class of multicomponent polymeric systems, where as in IPNs, the polymers are crosslinked, thus providing a mechanism for controlling the domain sizes and reducing creep and flow. Though the idea behind IPN synthesis is to effect molecular level interpenetration of the polymer networks, most IPNs form immiscible systems with phase separation during some stage of synthesis. Aylsworth, in 1914 invented the first known IPN, but the term IPN was coined much later in 1960, by Millar who developed PS/PS IPNs to be used as ion exchange resin matrices (Aylsworth, US Patent 1, 111, 284, 1914), (Millar, J. Chem. Soc. 1311, 1960). The literature review shows that Sperling and coworkers at Lehigh university, USA followed by Frisch from University of Detroit and Frisch from Suny, Albany have made the most contributions to this research area. The current review on IPNs summarises the processing, properties and applications of IPNs, with special focus on some recent developments and trends.