Molecular demixing in poly[cross‐(ethyl acrylete)]‐inter‐poly[cross‐(methyl methacrylate)] interpenetrating polymer networks brought about by selective decrosslinking and annealing

The extent of molecular demixing of poly[cross‐(ethyl acrylate)]‐inter‐poly[cross‐(methyl methacrylate)] interpenetrating polymer networks (PEA/PMMA IPNs), of mid‐range composition was investigated by decrosslinking and/or annealing using dynamic mechanical spectroscopy. A single broad transition characteristic of extensive but incomplete molecular mixing was observed for the PEA/PMMA IPN. The presence of crosslinking in both phases of an IPN enhances the mutual miscibility of the polymers. Through the use of a labile crosslinker, acrylic acid anhydride (AAA), polymer networks may be decross‐linked, allowing the chains to separate and form two distinct phases. Annealing further sharpens the transitions, and phase separation becomes most pronounced when decrosslinking is followed by annealing.