Synthèse et propriétés de polyuréthannes réticulés par des cycles isocyanurates

The reaction of α-ω-hydroxy-terminated polyethers or polybutadienes and diphenyl methane diisocyanate in presence of a basic catalyst, such as triethylene or dibutyl tin dilaurate gives polyurethane networks. IR spectroscopy shows that the networks contain isocyanurate rings. These rings are stable at high temperature showing a constant rubbery modulus from T_g up to 160°C. It is noted that the modulus varies with the formulation, the nature of the prepolymer and its molecular weight, the rate of diisocyanate and the catalyst as well as the possibility of introducing butanediol into the formulation.