Non-isothermal pyrolysis of pectin: A thermochemical and kinetic approach

The thermal degradation of pectin was investigated by simultaneous TGA-DSC/FTIR analysis and HiRes/modulated-TGA technique under nitrogen atmosphere. Pyrolytic degradation is a complex set of simultaneous and consecutive reactions related to: (i) dehydration at temperatures <= 100 degrees C; (ii) initial depolymerization by breaking the glycosidic linkages for temperature <= 210 degrees C, (iii) secondary degradation of the pectin units between 250 and 580 degrees C, and (iv) direct gasification of char residues at temperatures >= 600 degrees C. Three model-free-kinetics algorithms, Friedman (F), Kissinger-Akahira-Sunouse (KAS) and modulated TGA (MTGA), were used to predict the pyrolytic cracking kinetics. The results are discussed in terms of activation energy, the most probable mechanisms, and their relationship with the structure. (C) 2015 Elsevier B.V. All rights reserved.