Abstract The polyurethane (PU) isothermal curing reaction between the polyether triol and the polyaryl polymethylene polyisocyanate was investigated by high-pressure differential scanning calorimeter method at 40-100 ℃ with the carbon dioxide (CO2) atmosphere at the pressures of 0.1-9.0 MPa. The modified Kamal autocatalytic model and the isoconversional method were used to study the kinetics. The results showed that PU curing reaction in high-pressure CO2 atmosphere was accelerated and had higher final curing degrees compared with those in high-pressure helium atmosphere. With the rising of CO2 pressure, both PU curing rate and final curing degree increased. This was because the solvation effect of high-pressure CO2, which decreased the glass-transition temperature and viscosity of the polyurethane oligomers in the PU curing systems, thus intensified the mass transfer in curing process. Both the activation energies obtained by the diffusion-amended autocatalytic kinetic model and the apparent activation energies of different curing degrees calculated by isoconversional method decreased with the increase of CO2 pressure, which proved the promotion effect of high pressure CO2 on the PU curing reaction.
