Kinetic analysis of color changes in cellulose during heat treatment
This paper deals with the kinetics of the color changes of cellulose during heat treatment. The color of cellulose heated at 90–180°C was measured by a spectrophotometer and expressed by CIELAB color parameters. The values of L* decreased and those of a*, b* and Δ E* ab increased at all the treatment temperatures. Several kinetic models, namely, the zero-order, first-order, second-order and autocatalytic model, were applied to the changes in the color values. Furthermore, the results of kinetic analysis using the best-fit model were compared to the results obtained from conventional kinetic models. It was suggested that the kinetic analysis using the best-fit model was the better way to accurately predict color changes during heat treatment. The values of apparent activation energy calculated from the changes of L*, a*, b* and Δ E* ab were 125, 124, 118 and 120 kJ/mol, respectively. These values were similar to the reported values calculated from other chemical or mechanical properties.