Reactivity of isocyanates with urethanes: Conditions for allophanate formation

A. Lapprand (1) , F. Boisson (1) , F. Delolme , Françoise Méchin (1) , J.-P. Pascault (1)

1 IMP - Ingénierie des Matériaux Polymères

The reactions between two polyisocyanates, 4,4#-methylenebis(phenyl isocyanate) (MDI) and trimer of isophorone diisocyanate (tIPDI) and a model arylealkyl diurethane were carried out at high temperature (>=170 °C) and several NCO/urethane ratios. A combination of 1H and 13C NMR and MALDI-TOF spectroscopies was used and allows the identification of reaction products. When MDI or tIPDI is reacted with a diurethane at high temperature and after cooled, allophanates are formed but not isocyanurates. 13C NMR was used to quantify the different reaction products obtained under different experimental conditions. Only a few allophanates (%10%) are obtained after 1 h of reaction.

Mots clés: allophanate; NMR; MALDI-TOF; Urethane

Domaines: Polymères; Matériaux

A. Lapprand, F. Boisson, F. Delolme, Françoise Méchin, J.-P. Pascault. Reactivity of isocyanates with urethanes: Conditions for allophanate formation. Polymer Degradation and Stability, 2005, 90 (2), pp.363-373. ⟨10.1016/j.polymdegradstab.2005.01.045⟩. ⟨hal-02045556⟩