Pyrolysis kinetics of tannin–phenol–formaldehyde resin by non-isothermal thermogravimetric analysis

Abstract

The interest of using tannin–phenol–formaldehyde (TPF) resin as adhesive for industrial and building material application is growing fast. Because of copolymerization among tannin, phenol, and formaldehyde molecules, TPF resin has better thermal stability than phenolic resin. The goal of this paper is to investigate the thermal degradation behavior of TPF resin by thermogravimetric analysis and to summarize and verify the favorable pyrolysis kinetics model corresponding to bio-based phenolic resin. For this purpose, a comprehensive study was conducted to reveal the thermal behavior of TPF resin. Firstly, a model containing three pseudo-components was used to describe the overall pyrolysis process performed at three constant heating rates. Then, bi-Gauss method, an asymmetric multi-peak fitting function was applied to separate the overlapping peaks. Kinetic parameters and kinetic mechanism of each separated peak were determined by model-free isoconversional method and y(α) and z(α) master plots, respectively. Finally, the pyrolysis kinetics model was validated to prove its prediction ability. With results of the apparent activation energies, pre-exponential factors, and the most probable kinetic mechanism functions, the simulated data of reaction model agreed with experimental data well. Therefore, these procedures and results can help improve the industrial performance of TPF resin.