New Aspects and Tasks of Differential-Thermal Analysis in Wood Chemistry

Thermal analysis of eucalptus camaldulensis and cotton stalks at different heating rates

“…Domansky and Rendos [13] compared the DTA curves of different lignin preparations in vaeuo and concluded that the degradation pattern was virtually the same for each. An endotherm extended from about 100 to 180 ~ and was followed by an exotherm at about 400 ~ [14]. On changing the heating rate from 1.0 to 12 deg/min sharp peaks appeared in the curve Fig.…”

“…It is well known that the infrared band at 3000 to 3600 cm -1 of wood is the superposition of many hydroxyl groups absorbing at different states of hydrogen bonding the 3400 cm -1 absorption was assigned to the intermolecular hydrogen bonded hydroxyl groups in the 101 plane, while the 3350 cm -1 band is the absorption of intra-molecular hydrogen bonded hydroxyl groups in cellulose [16]. Therefore, the shift of the hydroxyl absorption maxima to a lower wave number may indicate the loss of intermolecularly bonded hydroxyl groups to form anhydroceUulose or the other macromolecular components of wood [14]. On further heating of the wood to temperature higher than 300 ~ , the loss of overall hydroxyl band intensity suggests degradation of intermolecular-bonded hydroxyl groups.…”

Thermal analysis of some lignin model compounds

“…IR spectra were taken of the samples in the form of KBr pellets with a UR-20 Zeiss spectrophotometer. The calculation of concentration of paramagnetic centres (PMC) was made from electron paramagnetic resonance (EPR) spectra taken with an RE-1301 radiospectrometer directly during heating using diphenylpicrylhydrazyl as standard, and from thermal data [3].…”