Diels-Alder Reaction of N-(benzocyclobuten-4-yl) Maleimide and Its Polymers Thermostability

Diels-Alder reaction of N-(benzocyclobuten-4-yl) maleimide monomer with itself under heat is explored firstly.At the same time,the radical copolymers of this monomer with styrene(St) and N-phenyl maleimide(NPMI) are prepared and the Diels-Alder reactions of the copolymers with NPMI are studied,too.The structures of the polymers are characterized by means of IR and 1H NMR.The thermal stabilities of the polymers are studied by TGA.The results indicate that the DANBCBMI has high decomposition temperature(i.e.the onset of decomposition temperature is 500℃ and only 32.21% weight loss is observed at 600℃).The thermal stabilities of the polymers increase slightly after Diels-Alder reaction but the solubility of polymers decreases.