Self-crosslinkable polymers from furan-functionalized Meldrum's acid and maleimides as effective precursors of free-standing and flexible crosslinked polymer films showing low dielectric constants

Furan-functionalized Meldrum's acid (MAF) has been utilized as a monomer for the preparation of self-crosslinkable polymers which possess Meldrum's acid (MA) moieties as the reactive sites. As MAF contains acidic C–H and furan groups, both are reactive toward maleimide groups, and polymerization has been carried out between MAF and multi-functional maleimide compounds. Both linear and hyperbranched MA-containing self-crosslinkable polymers have been prepared. The prepared polymers show good solubility in aprotic high polar solvents and high film formability. Self-standing and highly flexible crosslinked films have been obtained. The polymer film shows high solvent resistance, a high glass transition temperature of 298 °C, a high thermal stability above 340 °C, and attractive mechanical properties with a Young's modulus of 3.58 GPa and a stress at break of 34.4 MPa. Moreover, the crosslinked polymer films have relatively low-dielectric constants of about 2.85–2.78. An effective approach has been demonstrated for the preparation of high molecular weight MA-containing polymers and the corresponding thermosetting resin based self-standing and flexible polymer films.