Kinetic and 13C NMR study of oxygen incorporation into PVC- and pitch-derived materials
Altoé, Gisele F. Freitas, Jair C.C.
Kinetic and 13C NMR study of oxygen incorporation into PVC- and pitch-derived materials - mar./abr. 2009 - 6 p. ; 1373-1378
Resúmen del autor: The kinetics of oxygen incorporation into a PVC-derived material with pitch-like characteristics was studied by isothermal thermogravimetric analysis at temperatures ranging from 200 to 270 °C. Activation energy, Ea, pre-exponential factor, A, and rate constants, kT, were obtained from the weight-gain curves recorded during reactions of the material with molecular oxygen, which were analyzed following a kinetic first-order model. The numerical values obtained were Ea = 100.5 kJ/mol and A = 1.6 × 1010 h-1. The extent of the oxidation at a fixed temperature was monitored by elemental analysis, and the chemical changes in the materials were followed by solid-state 13C NMR. The study was next extended to the chars obtained from three coal tar pitches with different softening points (55, 85, and 110 °C). Comparisons were then established between the determined kinetic parameters and the chemical/structural aspects and compositions of each analyzed material.
Kinetic and 13C NMR study of oxygen incorporation into PVC- and pitch-derived materials - mar./abr. 2009 - 6 p. ; 1373-1378
Resúmen del autor: The kinetics of oxygen incorporation into a PVC-derived material with pitch-like characteristics was studied by isothermal thermogravimetric analysis at temperatures ranging from 200 to 270 °C. Activation energy, Ea, pre-exponential factor, A, and rate constants, kT, were obtained from the weight-gain curves recorded during reactions of the material with molecular oxygen, which were analyzed following a kinetic first-order model. The numerical values obtained were Ea = 100.5 kJ/mol and A = 1.6 × 1010 h-1. The extent of the oxidation at a fixed temperature was monitored by elemental analysis, and the chemical changes in the materials were followed by solid-state 13C NMR. The study was next extended to the chars obtained from three coal tar pitches with different softening points (55, 85, and 110 °C). Comparisons were then established between the determined kinetic parameters and the chemical/structural aspects and compositions of each analyzed material.
