Synthesis and characterization of a novel end-capping monomer for PMR process and related PMR polyimide

摘要

@@Aromatic polyimide, because of their excellent thermal stability, good chemical stability and mechanical strength,as well as low dielectric constants, have been one of the most useful and important polymers, and have been widely used as materials for the microelectronic encapsulation, aviation, and separation etc. It is attested that PMR method (in-suit Polymerization of Monomer reactants) should be one of important methods to obtain heteroaromatic polymers with good solubility and processability, and PMR process is carried out by the initial formation of oligomeric prepolymers capped by a reactive end group,i.e.cis-5-norbornene-endo-2,3-dicarboxylic anhydride(NA), while the crosslinking structure formed by the reverse Dials-Aider reaction of NA end group at 270-290°C under a given pressure. The end cap facilitates processing by controlling the molecular weight of the oligomer and allowing flow before it cross-links. However, there are few reports on 5,6-dehydronorcantharidin (ONA) as end group in PMR process, and ONA would be obtained easily by Diels-Aider reaction based on furan and maleic anhydride(see Scheme 1), this will be an interesting topic for developing novel polyimids.