MSc Candidate, Ms. Shirel Feldman, M.Sc. Candidate (Haifa Campus)
Department of Materials Science and Engineering , Technion
Haifa 32000, Israel
Hydrogel polyHIPEs (HG-PHs) are macroporous, hydrophilic polymers synthesized within oil-in-water (o/w) high internal phase emulsions (HIPEs). Interpenetrating polymer networks (IPNs) are usually formed by synthesizing, simultaneously or sequentially, one polymer network in the presence of another and can be used to tune the macromolecular structure, and thus, achieve synergistic thermal and mechanical properties. Here, the synthesis and structures of four different HG-PHs with IPN structures are reported. One of the networks was a poly(urethane urea) (PUU) formed through the interfacial step-growth polymerization of pectin and hexamethylene diisocyanate. The second network was formed through the free radical polymerization of various hydrophilic monomers (hydroxyethyl methacrylate (HEMA), acrylamide (AAm), acrylic acid (AA) or 2-acrylamido-2-methylpropane sulfonic acid (AMPS)) and crosslinked using N,N’-methylenebisacrylamide. The macromolecular structures were confirmed using Fourier-transform infrared spectroscopy.
The IPN HG-PH exhibit open-cell porous structures and their tan peaks (dynamic mechanical thermal analysis) seem to reflect a relatively restricted macromolecular mobility as well as a wide variation in local composition. The water uptakes in the IPN HG-PHs reflect the PH’s porosity and the polar and/or ionic natures of the hydrophilic monomers. The mechanical behaviors of the dry IPN HG-PHs reflect the densities and the mechanical behaviors of the component networks, and those of the water-swollen IPN HG-PHs also reflect the water uptakes.