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 degrees C, 83.15 celcius and 199.75 celcius, 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 x 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.