Authors: Heitor Luiz Ornaghi Matheus Poletto Ademir José Zattera Sandro Campos Amico
Publish Date: 2013/10/25
Volume: 21, Issue: 1, Pages: 177-188
Abstract
The thermal degradation behavior of six different vegetal fibers was studied using thermogravimetry under nitrogen atmosphere at four different heating rates 5 10 20 and 40 °C min−1 The degradation models Kissinger Friedman and Flynn–Wall–Ozawa methods were used to determine the apparent activation energy and the frequency factor of these fibers Furthermore the solid state degradation mechanisms were determined using Criado’s method Additionally Xray diffraction and Fourier transform infrared FTIR spectroscopy were analyzed to corroborate the obtained results The results indicated that the apparent calculated activation energies can be more closely related to the exponential dependence of the rate of heterogeneous reactions than to the necessary “energy” which is commonly used The Criado’s master curves indicated two different degradation mechanisms for the fibers diffusion followed by random nucleation The results also indicated that the crystallinity index as calculated by Xray diffraction and determinated by FTIR does not necessarily represent higher thermal stability as noted by the thermogravimetric analysis curves The thermal behavior and the degradation mechanism did not show to be influenced by the lignocellulosic components of the fibers exception for buriti and sisal This behavior was attributed to higher extractive content
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