The application of the Diels-Alder reaction to polymers bearing furan moieties .1. Reactions with maleimides

Two types of furan-containing polymers, namely polyurethanes and acrylic copolymers, were used as reactive substrates for Diels-Alder cycloadditions with mono- and bis-maleimides. The role of the specific position of the heterocycle in the macromolecular chains, as well as its frequency along them, was studied in order to assess the ease with which the coupling occurred. Both the simple adducts derived from the monofunctional dienophiles and the crosslinked products arising from the coupling of the furanic polymers with the bisdienophiles were fully characterized. Attempts to return to linear structures by heating the latter materials, cia the retro Diels-Alder reaction, were not successful. (C) 1997 Elsevier Science Ltd.