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X-RAY PHOTOELECTRON SPECTROSCOPIC ANALYSIS OF CCA-TREATED WOOD

TitleX-RAY PHOTOELECTRON SPECTROSCOPIC ANALYSIS OF CCA-TREATED WOOD
Publication TypeJournal Article
Year of Publication1993
AuthorsRuddick, JNR, Yamamoto, K, Wong, PC, Mitchell, KAR
JournalHolzforschung
Volume47
Pagination458-464
Type of ArticleArticle
ISBN Number0018-3830
KeywordsCCA PRESERVATIVES, CHROMATED COPPER ARSENATE, ESCA ANALYSIS, FIXATION, LEACHING, LIGNIN, photoelectron spectroscopy, PINUS-PONDEROSA, PSEUDOTSUGA-MENZIESII, SURFACES, WATER REPELLENCY, X-RAY, XPS
Abstract

Ponderosa pine and Douglas-fir wood sections were treated with CCA preservative. To elucidate the mechanism of fixation of the CCA, the wood surface was analyzed by X-ray photoelectron spectroscopy (XPS). CCA treatment increased C1 (carbon bonded to carbon and/or hydrogen) and decreased C2 (carbon bonded to one oxygen) in XPS C1s spectra, in both unextracted and pre-extracted sections. This suggested oxidation of hydroxyl groups on cellulose and/or lignin by CCA occurred, followed by the decarboxylation of carbonyl and carboxyl groups. However, the large changes in the state of the carbon atoms recorded during CCA treatment of unextracted wood would appear to include combined effects of the migration of extractives to analyzed surfaces as well as the oxidation of hydroxyl groups in wood by CCA. Accelerating the fixation produced more C1 than fixation at ambient temperatures. This increase in C1 also correlated with a higher resistance to preservative leaching in wood in which the CCA was fixed under accelerating conditions. Surface concentrations of the CCA components determined by XPS were lower in wood in which the fixation was accelerated, and this may contribute to their lower water repellency. CCA treatment enhanced the water repellency of wood, especially in the presence of extractives.

URL<Go to ISI>://A1993ML94100002