A Study On Durability And Leaching Resistance Of Triazole Wood Preservatives

Laboratory sand-block, leaching resistance and field stake test of some formulations containing tebuconazle (TEB) and propiconazole (PPZ) were conducted in this paper. And an analytical method of the two compounds TEB and PPZ by High Performance Liquid Chromatography (HPLC) was also compared to the literature and modified in this paper.The anti-fungi performance of tebuconazle and propiconazole is evaluated by laboratory sand block test and field stake test. Different formulations of preservatives based on TEB and PPZ was inspected. In laboratory accelerated test, the brown rot fungi Gloeophyllum trabeum (G.t) and white rot fungi Coriolus versicolor (C.v) are used. The result shows that there is no significant difference of anti-fungi performance between TEB and PPZ. The rational retention of TEB and PPZ is no more than 240g/m3.When ratio by weight between TEB and PPZ is 1:1, the rational retention is as lower as 180g/m3. After more than two years field trial test, the test specimens in which the retention of activities are 180 g/m3 or more, perform a good resistance to decay. TEB and PPZ have a weak termite resistance, and it can be efficiently improved by adding pyrethroid in treating solution.An analytical method for determining TEB and PPZ in preservative or treated wood by HPLC is established. The apparatus and reagents: Elite P230 pump with 20μL loop injector; the column is Allsphere 150.0mm×4.6mm 5μm C18 column; UV detector with a measuring wavelength of 225 nm; EC2000 workstation; HPLC mobile phase is the mixture of acetonitrile, methanol and water in a volume ratio of 1:1:1; the flow rate is kept at 1.5 mL per minute. The retention time is 4.71mm for TEB and 5.66min for PPZ. The linear correlation of this method is 0.9992 for TEB and 0.9999 for PPZ at concentration of the activities from 2 to 40mg/L. The average recovery of spiked samples is 99.8% for TEB and 100.9% for PPZ, and relative standard deviation is 0.621% for TEB and 0.540 for PPZ. The detection limit of method was 0.5mg/L for TEB and PPZ.The leaching resistance of TEB and PPZ are mainly affected by the type of formulations. Leaching rate of TEB is from 30.2% to 42.1% in emulsion formulations and 7.7%～15.6% in solvent oil solutions. Leaching rate of PPZ is from 20.8% to 38.0% in emulsion formulations and 7.6%～15.0% in solvent oil solutions. The leaching rates of TEB and PPZ in solvent oil solutions are significantly lower than in emulsion formulations at different retention levels. In both emulsion formulations an solvent oil solutions, the TEB and PPZ leaching rates of treated wood at higher retention is lower than that of lower retention. In emulsion formulations, increase the proportion of emulsifying agent could reduce the leaching rate of TEB. Addition of copper complex in the formulations could reduce the leaching rate of TEB while equivalent retention of TEB in the copper triazole and in emulsion type.