Synthesis, characterization and thermooxidative stability of addition polymers from 1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracene and anthracene end‐capped imide oligomers

A series of Diels–Alder addition‐type copolymers prepared from 1,4,5,8‐tetrahydro‐1,4;5,8‐diepoxyanthracence and anthracene end‐capped 6F‐PDA imide oligomers were characterized. The composition of the anthracene end‐capped imide oligomers was found to be sensitive to monomer molar ratios and the mode of monomer addition. The resistance of the copolymer to thermooxidative degradation at 316 and 371°C was compared with a similar commercial polymer called Avimid‐N prepared from 4,4′‐hexafluoroisopropylidene‐2,2′ bis(phthalic acid anhydride) and para‐and meta‐phenylene diamine, abbreviated 6F‐PDA. There are strong indications that the copolymers undergo degradation initially by unzipping the diepoxyanthracene unit from the anthracene end‐capped 6F‐PDA oligomer unit (Avimid‐N like repeat unit), followed by a slower degradation of the more stable residual 6F‐PDA unit.