The Michael addition reaction of Meldrum's acid (MA): an effective route for the preparation of reactive precursors for MA-based thermosetting resins

Meldrum's acid (MA) could be considered as a precursor of a highly reactive ketene group, and consequently is a suitable group for building up crosslinkable small molecular compounds and polymer chains. In this work, the Michael addition reaction of MA is applied for the preparation of multifunctional MA-containing compounds, exploring an effective route to synthesize multifunctional MA compounds, used as monomers for the corresponding MA-based thermosetting resins. Moreover, MA is utilized as a difunctional monomer to be polymerized with a bismaleimide (BMI) through the Michael addition reaction. A polymerization method directly using MA as a monomer for the synthesis of reactive and crosslinkable MA-containing polymers (poly(BMI-MA)) is demonstrated. The corresponding crosslinked CR-poly(BMI-MA) sample shows a high glass transition temperature (315 °C), high mechanical strength and a low dielectric constant of 3.15 at 1 MHz. A new type of MA reactive route and the corresponding high performance crosslinked resins are demonstrated.