The Diels-Alder reaction of bis-(2-pyrone) 2 with various aliphatic an
d aromatic bismaleimides 1 in dilute solution was carried out to produ
ce linear soluble copolymers with a coronand structure. NMR spectra an
d model reactions confirm the structure 4 (3). The polymers show weigh
t losses at about 440 degrees C determined by thermogravimetric analys
is (Tab. 1).