Catalytic liquefaction of starch by sulfamic acid and its curing kinetics for preparing polyurethane

In this paper, starch was first liquefied using sulfamic acid as catalyst, and then the starch-based polyurethane coating was prepared. The optimum ratio between the hydroxyl group of liquefied starch and isocyanate group of PM200 was determined to be 1:1.3. Differential scanning calorimetry was used to study the curing reaction kinetics of starch-based polyurethane, and the result showed that the initial temperature (Ti), peak temperature (Tp) and end temperature (Tf) of thermostatic curing reaction were 23.31 °C, 83.15 ℃ and 199.75 ℃, respectively. According to the Kissinger model, the calculated activation energy and preexponential factor of the curing reaction system were 44.34 kJ mol−1 and 7.36 × 103 s−1, respectively. Meanwhile, the Crane model indicated that the order of curing reaction was 0.88. The curing kinetic equation was also established to provide a theoretical basis for the actual curing process of starch-based polyurethane materials.