Thermally reversible highly cross-linked polymeric materials based on furan/maleimide Diels-Alder adducts

A novel thermally reversible cross-linked polymer has been synthesized by a Diels-Alder (DA) reaction between bis(4-maleimido-phenyl)fluorene (cBMI) and tetrakis-furan monomers (4F) under microwave (MW) irradiation. The ultimate aim of this work was the preparation of a thermosetting material recyclable by a simple thermal treatment. The use of the MW irradiation was necessary because under thermal conditions the DA polymerization could lead to materials only partially cross-linked for a not desired equilibrium between DA and retro-DA processes induced by the high temperature. The easy thermal degradation of this cross-linked material was ascertained by appropriate experiments. Moreover, to better study the involved reactions of formation and decomposition, a more simple model-compound was also synthesized. The reported data confirm the recyclability of the synthesized cross-linked polymer by simply heating with the possibility of a regeneration of the polymer network by a further MW irradiation.