Copolyimides using 3-phenyl tricyclo [6,2,2,02,7] dodeca-2,11-ene-5,6,9,10-tetracarboxylic dianhydride as a thermosetting functional group: Preparation,characterization, and thermal curing chemistry

Copolyimides were prepared by the reaction of 4,4-oxydianiline (ODA) with two dianhydrides, namely, 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and 3-phenyl tricyclo 6,2,2,0^2,7] dodeca-2,11-ene-5,6,9,10-tetracarboxylic dianhydride (PTDDA). ODA and BTDA first reacted in DMAc solvent, then following the addition of PTDDA, which was used as a thermosetting functional group in the polymer's backbone. Two homopolyimides prepared from the reaction of ODA with BTDA or PTDDA were also synthesized. The properties of homopolyimides such as solubility, thermal properties, and thermal curing mechanism were compared to those of copolyimides. The results showed that the tricyclic structure of the PTDDA unit underwent a reverse Diels-Alder reaction at near 300°C and it controlled the thermal behaviors of copolyimides.