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Changes in composition and porosity occurring during the thermal degradation of wood and wood components

Scientific Investigations Report 2004-5292

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Abstract

Samples of pine and poplar wood, pine bark, and purified cellulose and lignin were charred at temperatures ranging from 250?C to 500?C for times ranging from 1 hour to 168 hours. Changes in composition were examined by Fourier Transform Infrared (FTIR) and 13C Nuclear Magnetic Resonance (NMR) spectrometry, mass loss, and elemental composition (carbon, hydrogen, and oxygen) of the char. Structural changes were examined by changes in porosity as measured by nitrogen gas adsorption. 13C NMR spectrometry, mass loss, and elemental composition were combined to estimate the mass of aromatic and aliphatic carbon remaining in the char. Mass loss and elemental composition were combined to estimate the chemical composition of material lost for various time intervals of heating. These analyses showed that aliphatic components in the test materials were either lost or converted to aromatic carbon early in the charring process. Nitrogen adsorption showed that no porosity develops for any of the test materials with heating at 250?C, even though substantial loss of material and changes in composition occurred. Porosity development coincided with the loss of aromatic carbon, indicating that micropores were developing within a fused-ring matrix.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Changes in composition and porosity occurring during the thermal degradation of wood and wood components
Series title:
Scientific Investigations Report
Series number:
2004-5292
Edition:
Online only
Year Published:
2005
Language:
ENGLISH
Description:
88 p.
Scale:
100000
Online Only (Y/N):
Y