Three types of wood preservatives, creosote oil (Creosote), chromated copper arsenate (CCA-3) and ammoniacal copper quats (ACQ-1) were studied, first by using thermogravimetric analysis (TGA) under different heating rates (5 or 40˚C/min), and then by using thermogravimetric analysis with infrared spectrometry (TGA-IR) and energy dispersive X-ray spectrometry (EDX). The results obtained from the TGA tests found that the decomposition temperature of each of the preservatives for the heating rate

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... t 5˚C/min was lower than that at 40˚C/min. Regardless of different heating rate, the char (wt %) of the CCA-3 was more than that of the ACQ-1, and the amount of char for the Creosote was lower than that for either of the water-based preservatives. The IR response of all preservatives in the TGA-IR tests showed that at a heating rate of 5˚C/min, the absorbance of Creosote and ACQ-1 was higher than that of CCA-3. This indicated that the concentration of evolved species of CCA-3 was less than that of Creosote and ACQ-1. However, at a heating rate of 40˚C/min, the absorbance of CCA-3 and ACQ-1 was higher than that of Creosote. Considering the decomposition step (thermal time or temperature) at different heating rates in the TGA tests and the IR response from the TGA-IR analysis, the results obtained showed that at the slow-heating regime, the concentrations of CO 2 produced by Creosote and ACQ-1 were higher than that of CCA-3, but at the fast-heating regime, the concentration of CO 2 for ACQ-1 was higher than that of Creosote and CCA-3. The EDX analysis of all preservatives showed that the main element of the char for Creosote was C (82.75%) after combustion. The char of CCA-3 had an amount of Cr (34.99%) that was obviously more than that of As (11.89%) and Cu (16.69%) due to Cr being a stable element during combustion. The char of ACQ-1 left a high amount of inorganic metal elements, such as Cu (50.14%). These results, when compared to the chemical ingredients of all preservatives, enabled us to point out the kinds of evolved species for referencing the thermo-decomposition processes of the preservatives. The use of TGA for analyzing the thermal properties of three types of preservatives, in combination with TGA-IR and EDX analysis, has led to useful results, regarding the identification of thermal decomposition products (evolved species and char).