Progress 07/01/09 to 07/01/14
Outputs
OUTPUTS: This report covers the period of July 1, 2009 to December 31, 2012. The effect of adding benign and non-fungicidal antioxidants and/or metal chelators on the performance of wood treated with several organic biocides was evaluated in laboratory and field tests. Preservatives included in the study were propoiconazole, tebuconazole, 4,5-dichloro-2-octyl-4isothiazolin-3-one and chlorothalonil, which were evaluated in exterior lap-joint tests, soil block decay test and accelerated laboratory soil contact tests. The results of these studies were presented at the 2009 and 2010 American Wood Protection Association meetings, at the International Forest Products Society meeting in Portland in 2011 and also at the 2012 International Research Group on Wood Protection meeting. The concept of using antioxidants and cheloators to enhance the activity of wood preservatives is based on the role of heartwood extractives in durable tree species. Consequently, a manuscript is being written with a co-author at another university on the formation and role of heartwood extractives. PARTICIPANTS: Dr. Darrel Nicholas, Professor of Forest Products at Mississippi State University was a co-investigator in this study and participated in authorship of the various publications. Mrs. Amy Rowlen, Mrs. Linda Sites and Mrs. Jenny Shi worked on this project. TARGET AUDIENCES: The primary target audiences are academic and industrial scientists involved in wood protection, including those studying heartwood with natural durability for the purpose of developing new environmentally benign wood protection systems. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Based on all of the data from laboratory and outdoor exposed samples, we conclude that the use of benign and non-fungicidal antioxidants and/or metal complexing additives enhance the efficacy of all the organic biocides tested in this study. Consequently, the use of these benign additives provides a means of significantly enhancing the activity of organic wood preservative systems, which could result in the use of lower levels of toxic biocides. However, additional long term field testing will be required before these systems could be commercialized.
Publications
- Nicholas, D.D., Shi, J., Schultz, T:.P., Sites, L. 2012. Effect of antioxidants on the efficacy of organic wood preservatives in an accelerated soil contact decay test. International Research Group on Wood Protection. IRG/WP 12-30583.
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Progress 01/01/11 to 09/30/11
Outputs
OUTPUTS: Inspection of various sets of research wood samples treated with an organic biocide(s) with addition of nonbiocidal antioxidant and/or metal chelating additives and exposed in the laboratory or outdoors continues. Enhanced efficacy by combining non-biocidal antioxidant and/or metal chelating compounds with organic biocides continues to be observed. This concept is based on the role of heartwood extractives in durable tree species against decay fungi and/or termites. Consequently, a manuscript is being written with a co-author at another university on the formation and role of heartwood extractives. PARTICIPANTS: Dr. Darrel Nicholas, Professor of Forest Products at Mississippi State University, is a co-investigator of this study and co-authored several manuscript. Mrs. Amy Rowlen,Mrs. Jenny Shi, and Mrs. Linda Sites are Research Assistants and Mississippi State University and worked part-time on this project. Mr. Nathan Little, a former graduate student now enrolled in the Ph.D. Entomology program at Mississippi State University, and Dr. Joseph Dahlen, a former Ph.D. student in the Forest Products program at Mississippi State University, had earlier contributed research efforts and were listed as co-authors on one manuscript published this year. TARGET AUDIENCES: A presentation was given to wood preservation professionals at the Forest Products Society 65th International Meeting in 2011, and a presentation was given to professionals who attended the American Wood Protection Association annual 2010 meeting. A article was published in a professional international referred wood technology journal. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Based on all the data from laboratory and outdoor exposed samples, we conclude that the use of benign and non-fungicidal antioxidant and/or metal-complexing additives enhance the efficacy of all organic biocides against decay fungi. A presentation was made for the 2011 International Forest Products Society meeting in Portland on the results to date.
Publications
- Little, N., Rowlen, A., Shi, J., Nicholas, D., Schultz, T. 2010. Update of BHT, resin acids, and organic wood preservative systems, and other items of interest in wood preservation at Mississippi State University. American Wood Protection Proceedings 106:328-332.
- Schultz, T.P., Dahlen, J., Nicholas, D.D. 2011. Effect of resin acids and other extractives on dimensional stability and decay susceptibility of southern pine lumber in above-ground exposure. Abstract in: Forest Products Society 65th International Meeting, June 19th to June 22nd, 2011, Portland, OR. p. 70.
- Schultz, T.P., Nicholas, D.D. 2011. Efficacy of two organic biocides with co-added antioxidants. Holzforschung 65:771-773.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Studies employing non-biocidal additives to enhance the efficacy of organic biocides continue. Mini lap-joint samples, treated with propiconazole, wax, and with or without co-added propyl gallate and installed above-ground at Saucier, MS, were rated after six years of exposure. The samples co-treated with the antioxidant/metal chelator had increased efficacy compared to matched samples treated with only the azole plus wax. SYP sticks were treated with propiconazole/tebuconazole or DCOI, with and without BHT co-added, and exposed in an accelerated soil-contact laboratory decay test. After 18 months of exposure the efficacy of the azoles was definitely enhanced by BHT, and DCOI efficacy may also be increased by BHT. The organic biocide chlorothalonil (CTN) and the antioxidant BHT were milled to minute particles and dispersed in water, with this formulation successful employed to treat wood. Lap-joint samples were treated with this dispersed CTN formulation, with and without BHT and resin acid. After about 18 months in an accelerated exterior exposure, using dynamic MOE to measure fungal deterioration, minor decay was observed in some samples. The untreated/control samples showed the greatest decay and the CTN + BHT + Resin Acid-treated samples the least decay. Another non-biocidal compound was identified, calcium, which may work by an alternative mechanism than the additives which we have previously examined. Soil block experiments to test for possible synergism between calcium and two organic biocides are underway. PARTICIPANTS: Dr. Darrel D. Nicholas, Professor of Forest Products at Mississippi State University, was a co-investigator of this study and co-authored a manuscript. Mrs. Amy Rowlen and Mrs. Jenny Shi, Research Assistants at Mississippi State University, worked on this project. TARGET AUDIENCES: A presentation was given to wood preservative professionals who attended the American Wood Protection Association annual meeting. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The mini-lap jopint test shows that the co-addition of an antioxidant/metal chelator improved the performance of wood treated with the organic biocide propiconazole and a water repellent in an outdoor above-ground exposure. The accelerated laboratory soil-contact stick test showed that samples treated with the azole combination propiconazole/tebuconazole, or DCOI, were both enhanced by the presence of the antioxidant BHT. Lap-joint samples treated with a micronized chlorothalonil, with and without the antioxidant BHT and/or the metal chelatorresin acids, and placed in an accelerated exterior exposure showed some initial decay. The least decay was observed with all components present: biocide/antioxidant/metal chelator. A presentation was made to the 2010 American Wood Protection Association meeting and a paper written for this proceedings. With high but uneconomical calcium levels present, wood treated with an organic biocide had increased efficacy.
Publications
- Schultz, T.P., Nicholas, D.D. 2009. Effect of co-added antioxidants and/or metal complexing compounds on decay efficacy and biocide elaching of southern yellow pine (SYP) samples treated with 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOI) or azoles. American Wood Protection Association Proceedings 105:56-58.
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Progress 07/01/09 to 12/31/09
Outputs
OUTPUTS: A study, set up six years ago and installed in Saucier, MS employing mini lap-joint samples treated with the organic biocide propiconazole with 1% wax with and without various levels of the antioxidant/metal chelator compound propyl gallate co-added and exposed above-ground, was rated. The laboratory accelerated soil-contact test employing sticks treated with the organic biocides propiconazole/tebucinazole or DCOI, with and without the antioxidant BHT, continues to be rated by mechanical strength measurements every three months. An initial soil block test suggests that another non-biocidal compound, which which has not yet been studied, inhibits decay fungi. An experimental plan was written to further test this compound for possible synergism employing two organic biocides; the soil block test will be initiated in early 2010. The first experiment above will continue to be rated yearly, and the second experiment quarterly. A presentation was given to the American Wood Protection Association on recent results obtained with organic biocides combined with the antioxidants BHT or propyl gallate. PARTICIPANTS: Individuals: Tor P. Schultz, Principal Investigator; Collaborators, Darrel D. Nicholas, Department of Forest Products, Professor; Amy Rowlen, Department of Forest Products, Research Associate II; Linda Sites, Department of Forest Products, Research Associate III. TARGET AUDIENCES: The primary target audiences are scientists in wood protection, especially those studying heartwood with natural durability for the purpose of developing new environmentally-benign wood protection systems. Publications and presentations are the primary instruments that are, and will be, employed to deliver the results obtain in this project. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The mini-lap joint test shows that the co-addition of the antioxidant/metal chelator improved the performance of wood treated with propiconazole/wax. The accelerated soil-contact laboratory test indicates that the co-additon of BHT to propiconazole/tebuconazole for wood in ground contact had some positive effect; this test will need to be run for longer exposure periods to confirm the tentative results with propiconazole/tebuconazole. The samples with DCOI have not yet shown any strength loss, so these samples will also need to be exposured for additional time. A meeting was held with two industrial scientists which discussed, in part, their interest in further studies on employing non-biocidal additives with organic biocides in wood preservation which they hold one license in. A presentation and subsequent paper was made at the 2009 American Wood Protection Association, and another will be given at the 2010 American Wood Protection Assocatiion on these latest results.
Publications
- No publications reported this period
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