| Abstract: | A novel class of aromatic imide AB-monomers with benzocyclobutene and an alkyne (primarily phenylethynyl group) as the reactive units have been prepared. The monomers have been utilized in thermally induced Diels–Alder polymerizations. The differential scanning calorimetric study of the AB-monomers provided two observations: (i) primary acetylene began its homopolymerization (202°C max.) before the electrocyclic ring opening of benzocyclobutene (270°C max.); (ii) the phenoxy group connecting between phenylacetylenyl group and the aromatic imide fragment suppressed polymerization in Diels–Alder fashion. Furthermore, thermoxidative stability evaluation on the cured samples (250°C for 8 h and then 350°C for another 8 h under N2 atmosphere), carried out at 650°F (air) for 200 h, indicated the more rigid phenylethynyl phthalimide system was the most heat-resistant. |
