Thermal analysis and kinetic study of native silks

Abstract

In this study, X-ray diffraction (XRD), thermogravimetric (TG) analysis and differential scanning calorimetry (DSC) method were used to analyze the main characteristics of native silks, and to analyze the thermal degradation process of this native silks. Three methods were used: XRD to study its structure, TG to study the thermal degradation process and DSC to study the curve of native silks. The thermal decomposition kinetics of native silks was examined within the heating rates of 5–20 °C min−1 in nitrogen atmosphere. Different models of kinetic analysis were used to calculate the activation energies using thermogravimetric data of the thermal degradation process. The activation energies got from Kissinger, Flynn–Wall–Ozawa and Satava–Sestak models were 217.49, 216.09 and 193.61 kJ mol−1, respectively. The values of activation energy indicated that the thermal degradation of native silks was a single reaction mechanism or the combination of multi-reaction mechanisms. TG-FTIR analysis showed that the main pyrolysis products included water, methane, carbon dioxide, ammonia, and so on.