Thermodynamics and kinetics of polyglycidyl nitrate-based urethane network formation by microcalorimetry

Abstract

The thermodynamics and kinetics of the curing reactions between polyglycidyl nitrate (PGN) and toluene diisocyanate, isophorone diisocyanate, and polyaryl polymethylene isocyanate (PAPI) were studied by microcalorimetry. The reaction rate between PGN and PAPI was the fastest among the three reactions above. Three thermodynamics (i.e., activation enthalpy, entropy, and free energy), rate constant, and three thermokinetic parameters (i.e., activation energy, pre-exponential constant, and reaction order) of the curing reactions were obtained by calculating the results of the reaction between PGN and PAPI at a series of temperature from 303.15 K to 318.15 K. The linear relationship between lnk and the mole ratio of the isocyanate and hydroxyl groups was observed. The corresponding kinetic equation describing the curing reaction between PGN and PAPI was dα/dt = 10−3.83(1 − α)3.04 at 318.15 K.