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

A novel thermally reversible cross-linked polymer was synthesized by a Diels-Alder (DA) reaction between bis(4-maleimido-phenyl)fluorene (cBMI) and tetrakis-furan monomers (4F) under microwave (MW) irradn. The ultimate aim of this work was the prepn. of a thermosetting material recyclable by a simple thermal treatment. The use of the MW irradn. was necessary because under thermal conditions the DA polymn. could lead to materials only partially cross-linked for a not desired equil. between DA and retro-DA processes induced by the high temp. The easy thermal degrdn. of this cross-linked material was ascertained by appropriate expts. Moreover, to better study the involved reactions of formation and decompn., a more simple model-compd. 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 irradn.