Calorimetric and Kinetic Analysis of Thermal Behaviors of Chrome-tanned Collagen Fibers Using Isoconversional and Multivariate Non-linear Regression Methods

Abstract

To further understand the thermal stability of collagen in hideand leather, the thermal denaturation behaviors of chrometannedcollagen fibers were studied by non-isothermaldifferential scanning calorimetry (DSC) using isoconversionaland multivariate non-linear regression (Multivar-NLR)methods. The differential (Friedman) and the integral (Ozawa-Flynn-Wall) isoconversional methods as well as the Multivar-NLR method showed that the denaturation (or shrinkage)process could be best described by a three-step model, in whicha reversible reaction was followed by a rate-limited irreversiblestep. The simulation of thermal behaviors of collagen at differenttemperature conditions indicated that the denaturation kineticscould be approximated to a one-step irreversible reaction at lowheating rates or temperatures. For the design of new chrome-freetanning systems, which can endow collagen with high enoughthermostability, the decrease in the rate of the irreversibledenaturation of collagen might be an important criterion as well,besides the increases in the denaturation (or shrinkage)temperature, enthalpy and effective activation energy.