Synergistic Wood Preservatives for Replacement of CCA

摘要

The objective of this project was to evaluate the potential synergistic211u001ecombinations of environmentally-safe biocides as wood preservatives. 211u001eDidecyldimethylammonium chloride (DDAC) was combined with either chlorothalonil 211u001e(CTN), tribromophenol (TBP) or sodium omadine (NaO) to provide the syntergistic 211u001emixtures. A total of five systems were examined; one oil-borne (DDAC:CTN) and 211u001efour water-borne (oil-in-water emulsions) mixtures, including DDAC:NaO with a 211u001ewater repellant. Wood treated with these preservatives was evaluated in both soil 211u001econtact and above-ground exposure, with CCA and pentachlorophenol (penta) treated 211u001ewood used as positive controls. The treated wood was evaluated for both biocide 211u001eefficacy and depletion. The water-borne DDAC:TBP and DDAC:NaO formulations 211u001eperformed poorly in the field tests and, consequently, are not viable wood 211u001epreservative systems. However, the addition of a water repellent to the DDAC:NaO 211u001esystem greatly improve the performance in above-ground tests, suggesting that 211u001ethis may be a good preservative for this application. The oil-borne DDAC:CTN 211u001eformulation is performing very well and may be viable wood preservation system. 211u001eThe water-borne DDAC:CTN formulation is performing moderately well at this time 211u001ebut appears to suffer from excessive CTN leaching; this deficiency probably can 211u001ebe corrected with a modified formulation.