Materials produced from plant biomass: Part I: evaluation of thermal stability and pyrolysis of wood

Abstract

This paper compares the thermal stability of the sawdust of different wood species, an important factor in producing reinforced polymers. The compositions of two wood species, Pinus taeda and Eucalyptus grandis, were determined to evaluate the influence of the main wood components on the thermal stability of this material. The two species were submitted to thermogravimetric analysis at different heating rates to calculate the activation energy (E a ) using the Flynn-Wall-Ozawa (FWO) and Kissinger methods. The results suggest that larger quantities of holocellulose and lignin associated with lower extractive contents give the wood greater thermal stability. The E a values calculated for the two species were in the range of 146-165 kJ.mol -1. Evaluation of the activation energy values offers a simplified means to better understand the thermal decomposition of the sawdust of different wood species used in developing composites.

Materials produced from plant biomass: part II: evaluation of crystallinity and degradation kinetics of cellulose

“…Figure 2 shows the TGA and derivative thermogravimetric (DTG) curves of the cellulose samples studied. A small weight loss for both samples occurs between 40-70 °C which is attributed to the removal of absorbed water in cellulose 14,31 .…”

Materials produced from plant biomass: part III: degradation kinetics and hydrogen bonding in lignin

“…According to the slope of this straight line E a /R the apparent activation energy E a can be calculated 10,11 . The order of reaction n is determined by Equation 2:…”

Structural Characteristics and Thermal Properties of Native Cellulose

“…Kinetic studies assume that the isothermal conversion rate, d /dt, is a temperature-dependent linear function while the conversion ( ) is independent of the temperature function according to Equation (8) [19][20][21]:…”

“…Equation (8) represents the rate of conversion at constant temperature according to the concentration of reactants at a constant rate. In this study, the conversion rate is defined by [19][20][21]:…”

“…These functions are shown in Table 1 through different g( ) expressions for the different solid state mechanisms [20,[22][23].…”