The effect of the isocyanate trimerisation catalyst on the chemical composition and strength characteristics of polyurethane-polyisocyanate foams

Nowadays polyurethane-polyisocyanurate (PIR) foams are in a wide use as structural and thermal insulation materials. Isocyanate trimerisation catalysts for foams synthesis have low selectivity in terms of isocyanurate formation. As a consequence, a significant number of target (primary) and (secondary) chemical processes occur during the synthesis of PIR foams. We estimated the dependence of isocyanate group consumption for the formation of the main primary and secondary products on composition isocyanate index by methods based on the internal standard. Indeed, with an increase in the isocyanate index, the conversion of isocyanate to isocyanurate decreases significantly. The paper examines the influence of trimerisation catalyst type on chemical composition and strength characteristics of PIR foams. Hence, catalysts based on organic salts of alkali metals are more selective to the isocyanate trimerisation process than tertiary amines and derivatives of quaternary ammonium bases.