Original Evaluation of Alkylammonium Compounds

Abstract--Didecyl dimethyl ammOnIum chloride, an alkylammonium compound (AAC) was tested for potential as a wood preservative using the method prescribed by Japanese Industrial Standard JIS A 9302 and by a technique developed at the New Zealand Forest Re-search Institute (NZFRI) for determining effectiveness of preservatives in protecting timber used in above-ground situations. Amendments to AAC treating solutions by addition of cupric chloride, which in practice may be required to increase activity against soft rot fungi, and am-monium hydroxide were evaluated to determine their effect on AAC activity against brown and white rot fungi. Cryptomeria japonica and Pinus radiata were used as test substrates and the effectiveness of the AAC solutions was compared with that of a proprietary copper-chrome-arsenate (CCA) preservative. At equivalent retentions, AAC was more effective than CCA in controlling decay in the JIS A 9302 test, but was less effective in the NZFRI test. Copper chloride and ammonium hydroxide amendments improved AAC effectiveness against white rot, but in dilute solutions adversely affected activity against brown rot. Differences in basic densities of the two test timbers resulted in differences in preservative retentions, particularly when these were expressed as a percentage weight/weight ratio, and some disparity in preservative effectiveness between each substrate was recorded