Polystyrene supramolecular networks based on DA-AD hydrogen bonds

Abstract

Then polystyrene supramolecular networks were prepared by radical copolymerization of styrene with monomers containing donor-acceptor (DA) moieties methacrylamide (MAAM) or 2-methacrylamidopyridine (MAP). The molar percentages of MAAM and MAP in the copolymers were, respectively, 2-20% and 6-40%. The glass transition temperatures (T g s) of these copolymers have been modeled by the Kwei equation showing secondary interactions due to intermolecular hydrogen bonds. The DA-AD association constants (K) have been calculated by 1 H NMR spectroscopy of MAAM and MAP. These constants were, respectively, 6.75 and 16.75 M −1 . Dynamic mechanical analyses by frequency and temperature sweep tests, were carried out in the molten state. Styrene-MAP or styrene-MAAM copolymers had higher moduli than neat polystyrene but the MAP influences the materials' properties distinctively from the MAAM. MAP copolymers had a second G′ plateau that appeared at 150°C, thus showing the formation of a supramolecular network.