Thermal Stability, Kinetic Degradation and Lifetime Prediction of Chitosan Schiff Bases Derived from Aromatic Aldehydes

Abstract

Abstract This study intends to synthesis chitosan‐aromatic aldehyde Schiff bases (ChSB) to investigate their thermal stability and kinetics degradation. All samples were characterized by FTIR, XRD and SEM techniques. Chitosan and chitosan derivatives were subjected to thermo‐gravimetric analysis, at four multiple heating rates 5, 10, 15 and 20 °C.min −1 . Calculations using two isoconversional integral methods, Flynn Wall Ozawa and Kissinger were performed. The changes in Entropy, Enthalpy, Gibbs free energy, and lifetime have been estimated. Thus, chitosan modification with aromatic aldehydes would have an accelerating effect on thermal decomposition. In addition, chitosan p ‐chlorobenzaldehyde were found to have the relative highest activation energy and the highest lifetime to thermally decompose amongst the other examined biopolymers. The kinetic process for the degradation of pure chitosan, chitosan‐ N,N ‐dimethylaminobenzaldehyde and chitosan‐ p ‐chlorobenzaldehyde was most probably described by an exponential function E 1 .While for chitosan‐ p ‐methoxybenzoaldehyde the function D 12 corresponding to a mechanism coupling “transfer and diffusion” seems to describe the degradation.