The relationship between preservative type and surface degrade in Pinus radiata
IRG/WP 3158
R S Johnstone, R K Bamber
Samples of Pinus radiata D. Don were impregnated with one of two preservative types, a copper chrome arsenic salt and a light organic solvent preservative. The panels were exposed to the weather for 4-5 years at a site near Sydney, Australia. Macroscopic and microscopic examinations showed different rates and patterns of weathering between the samples treated with each preservative and an untreated control. The sample treated with copper chrome arsenic salt indicated reduced lignin and cellulose degradation when compared to the untreated wood and the lignin and cellulose breakdown was greatest in the wood impregnated with light organic solvent preservative. Adsorption of copper and chromium onto lignin and cellulose appears to have stabilised the wood treated with copper chrome arsenic salt and the organic solvent preservative appears to have solubilised the lignin and facilitated weathering.