FORMATION OF POLY(URETHANE-ISOCYANURATE) NETWORKS FROM POLY(OXYPROPYLENE)DIOLS AND DIISOCYANATE

Reaction conditions leading to the smallest amount of unreacted isocya nate groups for the preparation of poly(urethane-isocyanurate) network s based on 2,4-tolylene diisocyanate and alpha,omega-dihydroxypoly(oxy propylene) (M(n) = 425-4000) were found. A tertiary amine, POLYCAT 41 , was used as a cyclotrimerization catalyst. The networks were prepare d by prepolymer two-stage technique. The content of isocyanate groups in the prepolymers and networks was determined by potentiometric titra tion. Model reactions in 1,4-dioxane were used for the estimation of p ossible reaction intermediates during poly(urethane-isocyanurate) synt hesis.