Wood Preservation Trends in North America - ACS Publications

Chapter 35

Wood Preservation Trends in North America

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H. M. Barnes Forest Products Laboratory, Forest and Wildlife Research Center, Mississippi State University, Mississippi State, MS 39762

This paper discusses recent trends in the wood preservation industry in North America. Particular emphasis is placed on the development of copper-rich second generation preservative systems, including problems (disposal, mold, copper leaching, and corrosion) and costs associated with the new systems. The effect of E P A restrictions on C C A is presented. Use and restrictions placed on current organic systems, especially creosote, are reviewed. Near and long term future directions for the wood preservation industry, including low level metallic systems, total organic preservative systems, combination systems, borates, the impact of substitute materials, and non-biocidal treatments such as polymer treatment, heat treatment, and chemical modification are covered. Finally, implications for new treatment processes and products such as engineered wood composites are presented.

© 2008 American Chemical Society In Development of Commercial Wood Preservatives; Schultz, T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.

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Introduction Wood preservation has changed dramatically since man first attempted to preserve wood. This paper will discuss modern timber preservation and the impacts changes have made in the industry. Following a short glance backwards to see where we have been, the current situation will be discussed and a look into the crystal ball of the future will be presented. By all accounts, the first reference to treating wood can be found with Noah's building of the ark. The early Egyptians attempted to preserve wood by coating them with natural oils. The Greeks made widespread use of durable woods and construction techniques which kept wood dry. Keeping wood dry remains our best method for preserving timber as attested to by the thousand year old timbers in Japanese shrines and temples and the 28 Scandinavian stave churches built after 1100 (1). The Romans continued the preservation techniques of the Greeks and extended it to treating boats with certain salts which reduced susceptibility to fire. Early chemical treatments for wood included treatment with mercuric chloride and blue vitriol (copper sulfate) as early as 1705. Crook (2) received an early colonial patent in the Province of South Carolina which incorporated the "Oyle or Spirit of Tarr". The modern timber preservation industry started in the 1830s. Kyan patented the use of mercuric chloride for treatment of rope, wood, and canvas in 1832 (3). The impetus for timber preservation in the U K was the Royal Navy and the need to protect British ships from destruction from shipworms, the major factor in the loss of the Spanish Armada in 1588. Moll and others used creosote to protect wood in 1836, but it was left to Behell (4) to devise a process to effectively treat wood and launch the modern timber preservation industry. In that same year, Boucherie was granted a French patent for his sap displacement method of treating with salt solutions (5). In the US, the railroads provided the impetus for the timber preservation industry. Burnett (6) used zinc chloride to treat wood, and this was a principal treatment for crossties in the US until the 1920s. The first commercial plant for waterborne salt treatments was built in 1848 in Lowell, M A for Kyanizing timbers. In the U.S., the first Bethell-process plan was built in 1865 in Somerset, M A . The advent of modern timber preservation in the US is linked to the production of crossties by the L & Ν Railroad at a plant in West Pascagoula (now Gautier), M S in 1875. Two other significant developments occurred in the 1800s. The first was the publication of Boulton's (7) treatise on wood preservation. The second was the pioneering work done in the pathology arena by Hartig (8), considered to be the father of forest pathology. Several excellent historical treatises on wood preservation during this early period can be found in the literature for readers interested in more detailed historical accounts (3, 9, 10). The author has also published

In Development of Commercial Wood Preservatives; Schultz, T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.

585 several reviews of wood preservation, preservatives and fire retardants, and processes which may have merit for the interested reader (11-16).

Older Preservative Systems Table 1 gives a listing of the important commercial preservatives developed prior to the 21 century. Preservative systems are generally classified as oils or oilborne systems, or waterborne systems. Downloaded by UNIV OF PITTSBURGH on May 3, 2015 | http://pubs.acs.org Publication Date: April 2, 2008 | doi: 10.1021/bk-2008-0982.ch035

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Table 1. Chronological listing of commercially important preservatives in North America Preservative Oils and Oilborne Systems Creosote Copper naphthenate Pentachlorophenol Waterborne Systems Zinc chloride Fluor-chome-arsenic-phenol Acid copper chromate Chromated copper arsenate Ammoniacal copper arsenate Ammoniacal copper zinc arsenate Borates Ammoniacal copper quaternary ammonium Copper azole, copper boron azole

Abbreviation

Year

CR CuN PCP

1831 1899 1931

FCAP ACC CCA ACA ACZA SBX ACQ CA, CBA

1838 1930s 1928 1938 1939 1980s 1980s (in US) 1990s 1990s

Creosote, an oil, is by far the oldest commercial system, coming to the fore with the development of Bethell's full-cell treating process. A brief history of creosote can be found in the literature (17). Copper naphthenate has been used as a wood preservative since 1889. It was first used in Germany and has been in commercial use since 1911, primarily as an amendment to creosote during World War II. It was recognized in the A W P A standards in 1949, but did not gain wide use for pressure treatments until the late 1980s when regulatory activities stimulated interest in the product because of its general use classification. Soon thereafter, copper naphthenate in #2 fuel oil began to be used for cross arms, bridges, utility poles, fence posts and lumber. Copper naphthenate is also used in non-pressure applications, including field-applied


586 preservatives and coatings (18). The last major commercial oilborne system is pentachlorophenol (penta) which is a crystalline chemical compound (C C1 0H), formed by the reaction of chlorine on phenol. British patent 296,332, issued to W. Iwanowski and J. Turski (19), covers the use of di-, tri-, and polychlorinated phenols for wood-preserving purposes. In the U.S., L.P. Curtin (20) patented the use of "chlorine derivatives of coal-tar acids of higher molecular weight than the cresols", expressing a preference for chlorinated phenols. The production of chlorinated phenols in the US for wood preserving experiments did not begin until about 1930(3). Chromated copper arsenate (CCA) was patented by Kamesam (21) in 1938 and, until 2004, was the major waterborne preservative in use in North America. Three forms were standardized by A W P A (22), type A in 1953, type Β in 1964, and type C in 1969 with type C dominating the marketplace today. The three types differ in their ratio of Cu:Cr:As. The voluntary withdrawal of C C A for most residential uses has greatly impact its consumption. A n additional acidic system, acid copper chromate (ACC or Celcure®) was patented in 1928 by Gunn (3) and was standardized in the 1950s. The other major arsenical preservative, ammoniacal copper arsenate ( A C A or Chemonite®) was standardized in 1950. It was modified by replacing some of the arsenic with zinc in the 1980s. This formulation is known as ammoniacal copper zinc arsenate ( A C Z A or Chemonite II®). Because A C A and A C Z A are alkaline and impart the wood with vivid color, they have generally been used for industrial, rather than residential, products and are used to treat refractory western conifers. During the early 1930s, Dr. Carl Schmittutz of Bad Kissingen, Germany, invented a process and formula for the preservation of wood. He organized the Osmose Wood Impregnating Company of Leipzig, Germany, and obtained patents for this process in many countries throughout the world, including the United States and Canada. The original Osmose patents described a preservative process using sodium fluoride, potassium bichromate, sodium arsenate, and dinitrophenol. This preservative was known in the industry as FCAP. Penetration of preservatives was achieved through the process of diffusion or "osmosis" into green wood or wood of high moisture content. One early commercial use of this preservative in the United States was a timber dipping and stacking process used by coal mines. These mines had a plentiful supply of green timbers that could be treated on-site for use as mine timbers. Another early use was the development of a paste formulation of F C A P preservative for in-place treatment of utility poles in the groundline area. Similar formulations and processes are still in use today for the groundline treatment of utility poles (23,24). Boron compounds offer some of the most effective and versatile wood preservative systems available today and combine the properties of broadspectrum efficacy with low acute mammalian toxicity. Oxides of boron, the active ingredients in boron systems, are ubiquitous within the environment, are


6


5

587 essential plant micronutrients, and are added regularly to agricultural land as fertilizers. Products treated with borates include the following: lumber, plywood, oriented strand board (OSB), siding, engineered wood, wood fiberplastic composites, millwork, windows, doors, furniture, telephone poles, railroad ties, and log homes (25).


New Wood Preservatives The major U.S. wood waterborne preservative was chromated copper arsenate (CCA), with oil-borne pentachlorophenol (penta) and creosote used to a lesser extent. C C A , along with smaller amounts of ammoniacal copper zinc arsenate ( A C Z A ) used in western North America and the mid-west, have been used to treat about 80% of all treated wood products in the U.S. (26) and have been the only systems used to protect lumber for residential applications. In 2004, about 6.1 billion board feet of the S Y P lumber was pressure treated with some type of preservative system (27), down 7% from the 2003 level due to residual inventory as treaters shifted to the new copper-based systems. C C A is an inexpensive and highly effective preservative and several E P A and other studies have found that CCA-treated wood poses negligible risk when used in residential construction, gardens, or for items such as playground equipment. However, recent public perceptions on possible arsenic exposure led to a rapid agreement to restrict the use of CCA-treated material to industrial applications by 2004 in the U.S. and in Canada. C C A has already limited use patterns in over 26 other countries. Since the largest market for treated wood is residential, this could reduce production of CCA-treated wood products by about 68%. Micklewright (26) showed that of the 581.4 million cubic feet of wood treated with waterborne preservatives, 477.8 million cubic feet were lumber and timbers, of which >98% was C C A . He reported a consumption of 74.4 million pounds of waterborne preservatives of which 98% would be 72.9 million lbs. By comparison, data for 2004 indicates that of the estimated 183.2 million pounds of waterborne preservatives used, only 58.2 million pounds were arsenicals representing 32% of the market for wood treated with waterborne preservatives (28). The balance of the waterborne preservative consumption was taken up by non-arsenicals such as borates, ammoniacal copper quats, copper azole, and acid copper chromate. These data can be seen in Table 2. The largest growth was seen in inorganic boron compounds, and the copper-rich A C Q and C A systems. Most European countries have already limited C C A use with further restrictions being considered, and Japan had quickly changed earlier to preservatives that do not contain arsenic or chromium. Even though many uses of C C A were voluntarily removed after Dec. 31, 2003, many use patterns will continue. Most of these uses are considered industrial uses and include such



Pounds (million, oxide basis, dry) 1.6

85.6

0.6

29.6

57.6

8.2 183.2

Waterborne Preservatives

ACC (acid copper chromate)

ACQ (ammoniacal copper quaternary ammonium)

ACZA (ammoniacal copper zinc arsenate)

CA (copper azole)

CCA (chromated copper arsenate)

SBX (inorganic boron)

Total

4.5

31.4

16.2

0.3

46.7

0.9

Percent of Total (All Compounds)

Table 2. Estimated ilndustry totals of each waterborne preservative consumed on a dry oxide concentrate basis hi 2004 (from Vlosky 2006).



589 things as poles, pilings, timbers. (6- χ 6-in or greater), posts, and other large members. CCA-treated stock for the permanent wood foundation is a notable exception to the withdrawal scheme. These may be found in the A W P A Book of Standards (22). Excellent coverage for most of the new generation preservative systems can be found in a soon to be published monograph (29). In the A C S Symposium Series (30), some thought provoking papers on new preservative systems can be found in the section on New Preservative-Protection Systems. In this series of papers, detailed discussions on A C Q , C A , C B A , and azoles can be found and will not be repeated here. Particularly interesting are the discussions on copper H D O (or copper xyligen/CX), a system recently standardized by A W P A , and P X T S (polymeric xylenol tetrasulfide), a new generation organic system also standardized by A W P A in 2005. A n organic 'cocktail' system consisting of tebuconazole, propiconazole, and imidacloprid is also being developed. Table 3 lists many of the newer systems being researched or being brought to standard along with other systems discussed in detail in this series of articles. Another interesting concept is to improve the performance of oranic preservative systems by adding non-biocidal additives, specifically antioxidants, metal chelators, or water repellent additives, that enhance the efficacy of and/or reduce degradation of organic biocides (31-33) There are several concerns with the second generation ammoniacal/amine copper systems. First, they are more expensive, costing 2-4 times more than C C A . The second major concern is corrosion. The increase in corrosion may be linked to the dissolution of zinc leading to increased attack on iron at the oxygen-wood interface. Increased mold growth is attributed to the newer systems, supposedly because of the enriched nitrogen environment. Part of this problem is perception since the molds growing on this treated substrate are whitish and hence more visible that the darker molds which were always present on CCA-treated wood. Because of concerns with the leaching of copper in these copper-rich systems, aquatic toxicity is a concern for marine uses. Disposal may also present some challenges. From a treating perspective, these newer systems are less forgiving and formulation is trickier than with C C A .

Wood Preserving Processes Little has changed commercially since the advent of pressure treatment of wood in the 1830s and the major treating processes have changed little since their inception. Bethell (4) patented the full-cell process for treating wood with creosote for the Royal Navy. In the early 1900s, two empty-cell processes were patented by Riiping (34) and Lowry (35). A detailed discussion of treating technology can be found in the literature (36) including discussions of the Oscillating Pressure Method, Alternating Pressure Method, Pulsation, Royal,


590


Table 3. New generation biocides for protection of wood. Borates Uncomplexed Copper Systems • ACQ • CA/CBA • Iron quats Complexed Metal-based Systems • Copper-8-quinolinolate • Copper H D O (copper xyligen) • CuN (waterborne) • ZnN • CDDC • TBTO Zinc Systems • Zinc/boron versatate • Zinc 8-hydroxyquinoline • Zinc naphthenate • Zinc + dicarboxylic acid hydrazide P X T S (polymeric xylenol tetrasulfide) PTI (propiconazole, tebuconazole, imidacloprid) Polymeric betaine Copper betaine Azoles • Cyproconazole • Propiconazole • Tebuconazole

Zirconium compounds Quaternary Ammonium Compounds • DDAC • ABAC • BAC • ADBAC • IPBC Synthetic Pyrethroids • Permethrin • Bifenthrin • Cypermethrin • Cyfluthrin • Deltamethrin Organic Agrochemicals • TCMTB • Chlorothalonil • Dichlofluanid • Isothiazolone • Fipronil • Imidachloprid • Methylene bis-thiocyanate



591 HPP, sap displacement (PresCap, SlurrySeal, Gewecke), Cellon, Dow, M S U , M C I , and Multi-Phase Pressure processes. A modern day refinement of the Bethell process, the modified full-cell process, has found widespread use in North America. In this process, the initial vacuum is reduced to 12-16 in Hg for a shorter time period than the conventional full-cell process. The final vacuum may be extended thus yielding treated wood with lower solution absorption of 22-32 pcf compared to 40 pcf for the conventional full-cell process. This results in much lower shipping and drying costs for wood, especially those treated with waterborne systems. There has been considerable interest in recent years in the development of vapor phase treatments for wood and wood composites. Treatment with gas phase components would eliminate the problems which exist with the liquid tension interface in current treatment practices (37). Trimethyl borate (TMB) has been successfully used to treat a wide range of wood composites (38-42). Even more fascinating is the potential for treating wood using supercritical C 0 (ScC0 ) as a carrier (43-45). In this case, there are no problems with the high surface tension associated with liquid treatment. Evans (46) reports that a plant for S c C 0 treatment has been commissioned in Denmark. The use of S c C 0 in composites is particularly appealing (47). Successful treatment of composites with a IPBC + silafluofen mixture has been achieved (48). S c C 0 treatment on a wide range of composites showed minimal loss in mechanical properties for most composites (49). The notable exception was a large loss of bending strength in OSB. Previously, K i m et al. (50) had shown some loss in bending strength when treating southern pine with T C M T B using S c C 0 treatment. For above-ground exposure in Hilo, Hawaii, Morrell et al. (51) showed excellent performance of plywood, M D F , particleboard, and OSB treated with tebuconazole using ScC0 .treatment so long as retention was high enough. Kang et al. (52) noted that the movement of cyproconazole in the S c C 0 treatment of ponderosa pine was influenced more by diffusion than by bulk flow. 2

2

2

2

2

2

2

2

The use of S c C 0 was originally developed to extract flavors or decaffeinate coffee. Its use to improve treatability of Douglas-fir by extracting fatty acids has been investigated (53). S c C 0 extraction has been used to extract PAHs and organo-chlorine compounds from wood, demonstrating its potential in waste recycling (54, 55). 2

2

Wood Modification Treatments As an alternative to biocide treatment, considerable research has been undertaken on wood modification treatments to improve the durability of wood and wood-based materials. Modification techniques have long been the 'holy



592 grail' of wood science and have been described quite elegantly by Stamm (56) in his classic treatise on wood science. A number of treatments including formaldehyde crosslinking, resin impregnation, and acetylation have led to increased durability. Much of the North American work in recent years has centered at the U S Forest Products Lab under the direction of Roger Rowell (57, 58). Most of this work has shown that acetylation and treatment with alkylene oxides enhance the durability of lignocellulosic materials. Graft copolymerizaton has been shown to have some value in improving the water repellency of wood (59), and polymer/boron systems have shown some efficacy (60). No commercial wood modification plants have been initiated in North America. International work on modification has centered in Europe which has developed a European Thematic Network for Wood Modification (61). Successful European Conferences on Wood Modification were held in 2003 and 2005. Silicone compounds and their derivatives have shown promise as water repellent agents (62, 63) and some derivatives, such as silafluofen, have shown promise as termiticides (48, 64). Acetylation and furfurylation (65) continue to be studied and commercialized in Europe and Japan. Dizman et al. (66) have reported good results with the modification of alder and spruce particleboards using acetic, maleic, succinic, and phthalic anhydrides. The major emphasis in Europe has been on the commercialization of heattreated wood (67, 68). Commercial operations (15-20 companies) in Finland, France, Germany, Austria, Switzerland, and Holland are supplying the marketplace with 200-300,000 m per year. Welzbacher and Rapp (69) indicate that commercially produced material from four processes increase the ground contact durability of wood, but not to the extent needed for ground contact applications. Evans (46) also presents an excellent discussion of wood modification, and a section on wood modification was presented at a recent conference (70). A n excellent monograph on wood modification treatments is available (71). 3

Concerns and Challenges Any discussion of trends must include some soul searching and crystal ball gazing. Some of the problems and concerns with second generation preservative systems were presented earlier. In all likelihood, these systems will remain viable for the next 10-15 years, but pressure on the use of heavy metals in preservative formulations, including copper, is worldwide. Several European countries have moved to eliminate systems containing copper. We are likely to see a move to all organic systems similar to the 'cocktail' system described earlier. These systems are already making headway in Europe. Organic systems



593 have some shortcomings which will need to be overcome. They are generally expensive and have limited bioactivity. They are either oilborne or formulated as emlsifiable concentrates or mirco-emulsions. This means either a more expensive carrier system in the case of oilborne systems or a trickier formulating process in the case of emulsions. The trick is to understand how to "solubilize" the insoluble actives and then add a mixture of anionic and cationic surfactants which enable dilution with water and dramatically improve reduction of leaching. Appearance of the treated wood may be a problem, and i f they are non-fixed systems, leaching could be problematic. The future may yield nanoparticle systems and micro-emulsions. In all likelihood, we will be faced with a shorter service life for treated wood. Lower retentions mean less environmental impact. Envelope treatments may become more commonplace and barrier wraps may be employed to boost service life. Society is becoming chemophobic which makes non-biocidal treatments more attractive. The use of antagonistic microbes may lead to improved durability. The use of emerging technologies to marry wood and other materials could lead to products with increased durability. Challenges abound for wood preservation and treated wood products. Four critical challenges face the industry: the mold issue, Formosan termite, engineered wood composites, and public education. The mold issue is an emotional one (72), and the C D C (73) has stated that no scientific proof exists that Stachybotrys has caused health problems. "The mold issue has only become a problem because the public now perceives it as a health threat and . . . attorneys are bringing the issue before juries to seek large judgments." (16). The devastating hurricanes of 2005 have exacerbated the problem. Amburgey (74) has presented some common sense solutions to the clean-up of the mold problem. In all instances the first rule should be - cure the moisture problem! The Formosan termite has become a $2 billion+ problem in coastal areas south of the 35° parallel. In the affected areas, there is a high demand for treated wood. Borate-treated stock for above ground applications would seem a good start on a solution. Research in Hawaii, Mississippi, and Louisiana is aimed at elimination of this threat. Engineered wood composites (EWC) are the wave of the future. Increasing the durability of these building materials is essential. Considerable research is being focused on E W C (75) as new E W C products, biocide addition methods, and preservative systems are brought forward. The extensive work being done on E W C durability modeling should prove a boon to our understanding (76-78). Lastly, we simply must do a better job of public education. The public perceives a health risk with treated wood, whether real or imagined. Few are familiar with consumer information sheets which accompany treated wood products. It is incumbent on the industry to improve technology transfer so the public can deal with the real facts about wood preservation and treated wood products.


594


References 1. Jjensenius, J. H. U R L http://www.stavechurch.org/index.html. 2. Crook, William. Province of South Carolina Patent No. 19, 1716. 3. Hunt, G. M.; Garratt, G . A. 1967. Wood Preservation. McGraw-Hill. New York, 1967. 4. Bethell, J. British Patent No. 7731, 1838. 5. Burt, H. P. Minutes of Proceedings, Institution of Civil Engineers (London) 1853, 12, 206-43. 6. Burnett, W . British Patent 7747, 1838. 7. Boulton, S. B . Minutes of Proceedings, Institution of Civil Engineers (London) 1884, 78, 97-211. 8. Hartig, R. Textbook of the Diseases of Trees. MacMillan and Co. New York, 1894. (translation from the German (Lehrbuch der Baumkrankheiten) by W. Sommerville). 9. Graham, R. D . Wood Deterioration and Its Prevention by Preservative Treatments. Vol. I. Degradation and Protection of Wood, Syracuse Univ. Press. Syracuse, N . Y , 1973, Chapter 1. 10. Wilkinson, J. G . Industrial Timber Preservation. Associated Business Press, London, England, U K , 1979. 11. Barnes, H . M. Forest Prod. J. 1985, 35 (1), 13-22 12. Barnes, H . M. Proceedings, The First International Symposium on the Development of Natural Resources and Environmental Preservation, New Horizons in Agricultural Science, Institute of Natural Resources and Environment, Korea University, Seoul, Korea, 1992, 161-198. 13. Barnes, H . M. Proceedings, 1993 Eurowood Oxford Fire Conference, Timber Research & Development Association, Mansfield College, Oxford University, Oxford, England, U K , 1993. 14. Barnes, H . M. Int. Res. Grp. on Wood Pres., Doc. No. IRG/WP/93-30018, 1993. 15. Barnes, H. M.; Murphy, R. J. Forest Prod. J. 1995, 45(9), 16-26. 16. Freeman, M. H . ; Shupe, T. F.; Vlosky, R. P.; Barnes, H . M. Forest Prod. J. 2003, 53(10), 8-15. 17. Barnes, H . M.; Ingram, L . L . Proceedings, American Wood-Preservers' Association 1995, 91, 108-117. 18. The Pacific Wood Preserving Companies. U R L http:// www.pacificwood.com/ faq2.cfm?FaqID=70 19. Iwanowski, W.; Turski, J. British Patent No. 296,332, 1928 20. Curtin, L. P. US Patent No. 1,722,323, 1929. 21. Kamesan, S. U.S. Patent No. 2,106,978, 1938 22. American Wood-Preservers' Association. Book of Standards. A W P A , Selma, A L , 2005. 23. McNamara, W.S. Proceedings, First International Conference on Wood Protection with Diffusible Preservatives, Proceedings 47355, Forest Products Research Society, Madison, WI, 1990, 19-21. In Development of Commercial Wood Preservatives; Schultz, T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.


595 23. McNamara, W.S. Proceedings, First International Conference on Wood Protection with Diffusible Preservatives, Proceedings 47355, Forest Products Research Society, Madison, WI, 1990, 19-21. 24. Osmose. U R L http://www.osmose.com/about/history/ 25. US Borax. U R L http://www.borax.com/borates2g.html (see also http://www.borax.com/wood/) 26. Micklewright, J. T. Report to the Wood Preserving Industry in the United States, American Wood-Preservers' Association, Granbury, T X , 1998. 27. Southern Forest Products Association. U R L http://www.sfpa.org/industry_statistics/SP_treated.htm 28. Vlosky, R. P. Report to the Southern Forest Products Association, Kenner, L A , 2006. 29. Freeman, M. H . ; Nicholas, D. D.; Schultz, T. P. Environmental Impacts of Treated Wood, C R C Press, Boca Raton, F L (in press). 30. Goodell, B.; Nicholas, D . D.; Schultz, T. P. (eds.). Wood Deterioration and Preservation: Advances in Our Changing World, A C S Symposium Series 845, A m . Chem. Society, Washington, D C , 2003. 31. Schultz, T.P., D.D. Nicholas. Phytochemistry 2000, 54, 47-52. 32. Schultz, T.P.; Nicholas, D. D. Phytochemistry 2002, 61, 555-560. 33. Schultz, T.P.; Nicholas, D . D ; Henry, W. P.; Pittman, C . U.; Wipf, D. O.; Goodell, B . Wood & Fiber Science 2005, 37(1), 175-184. 34. Ruping, M. U. S. Patent No. 709,799, 1902 35. Lowry, C. B . U. S. Patent No. 831,450, 1906. 36. Barnes, H . M. Proceedings, Wood Protection 2006, Forest Products Society, Madison, WI (in press). 37. Scheurch, C. 1968. Forest Prod. J. 1968, 18(3), 47-53. 38. Hashim, R; Dickinson, D. J.; Murphy, R. J.; Dinwoodie, J. International Res. Group on Wood Preservation, Doc. No. IRGIWP/3727-92,1992. 39. Hashim, R; Dickinson, D. J.; Murphy, R. J.; Dinwoodie, J. Forest Prod. J. 1994, 44(10), 73-79. 40. Barnes, H . M.; Murphy, R. J. Wood & Fiber Science 2005, 37(3), 379-383. 41. Barnes, H . M.; Murphy, R. J. Composites Part A: Applied Science and Manufacturing (in press). 42. Murphy, Richard J; Barnes, H . Michael; Dickinson, David J. Proceedings, Enhancing the Durability of Lumber & Engineered Wood Products, Publication No. 7249, Forest Products Society, Madison, WI, 2002, 251255. 43. Junsophonsri, S. Solubility of biocides in pure and modified supercritical carbon dioxide. Unpublished Master's thesis, Oregon State Univ., Corvallis, OR, 1994. 44. Morrell, J.J.; Levien, K . L . ; Demessie, E. S.; Kumar, S.; Smith, S.;Barnes, H . M . 1993. Proc., Canadian Wood Preservation Assoc. 1993, 14, 6-25.



596 45. Morrell, J.J.; Levien, K . L . ; Demessie, E. S.; Barnes, H . M. Proc., Inter. Conf. on Wood Poles & Piles, Colorado State Univ., Ft. Collins, C O , 1994, 325-337. 46. Evans, P. Forest Prod. J. 2003, 53(1), 14-22. 47. Oberdorfer, G.; Humphrey, P. E.; Leichti, R. J.; Morrell, J. J. International Research Group on Wood Preservation, Doc. No. IRG/WP 00-40175, 2000. 48. Tsunoda, K . ; Muin, M . International Research Group on Wood Preservation, Doc. No. IRG/WP 03-40251, 2003. 49. Muin, M.; Adachi, Α.; Tsunoda, K . International Research Group on Wood Preservation, Doc. No. IRG/WP 01-40199, 2001. 50. K i m , G. - H ; Kumar, S.; Demessie, E. S.; Levien, K . L . ; Morrell, J. J. International Research Group on Wood Preservation, Doc. No. IRG/WP 9740080, 1997. 51. Morrell, J. J.; Acda, M . N.; Zahora, A . R. International Research Group on Wood Preservation, Doc. No. IRG/WP 05-30364, 2005. 52. Kang, S-M.; Levien, K . L . ; Morrell, J. J. Wood & Fiber Science 2006, 38(1), 64-73. 53. Kumar, S.; Morrell, J. J. International Research Group on Wood Preservation, Doc. No. IRG/WP 93-40008, 1993. 54. Schrive, L . ; Perre, C.; Labat, G. International Research Group on Wood Preservation, Doc. No. IRG/WP 98-50101-18a, 1998. 55. Legay, S.; Marchai, P.; Labat, G . International Research Group on Wood Preservation, Doc. No. IRG/WP 98-50101-18b, 1998. 56. Stamm, A . J. Wood and Cellulose Science. Ronald Press. New York, 1964. 57. Rowell, R. M . Handbook on Wood and Cellulosic Materials. Marcel Dekker, Inc. New York, 1991 58. Rowell, R. M. 1999. Proceedings, International Workshop of Frontiers of Surface Modification and Characterization of Lignocellulosic Fibers. Fiskebackskil, Sweden, 1999, 31-47. 59. Morshed, M. M.; Nicholas, D. D.; Pittman, Jr., C. U . ; Schultz, T. P. International Research Group on Wood Preservation, Doc. No. IRG/WP 0340257, 2003. 60. Murphy, R. J.; Barnes, H . M.; Gray, S. M. Forest Prod. J. 1995, 45(9), 7781. 61. Jones, D.; Homan, W.; Van Acker, J. International Research Group on Wood Preservation, Doc. No. IRG/WP 03-40268, 2003. 62. Rowell, R . M . ; Banks, W. B . Water repellency and dimensional stability of wood. U S D A Forest Service, Forest Products Laboratory, General Technical Report FPL-50, Madison, WI, 1985, 24 pp. 63. Hager, R. International Research Group on Wood Preservation, Doc. No. IRG/WP 95-30062, 1995. 64. Adams, A . J.; Jermannaud, Α.; Serment, M . -M. 1995. International Research Group on Wood Preservation, Doc. No. IRG/WP 95-30069, 1995.



597 65. Balfas, J.; Evans, P. D . International Research Group on Wood Preservation, Doc. No. IRG/WP 94-40017, 1994. 66. Dizman, E.; Yildiz, Ü.; Kalaycioglu, H.; Yildiz, S; Temiz, Α.; Gezer, E . D. International Res. Group on Wood Preservation, Doc. No. IRGIWP/0540300, 2005. 67. Tjeerdsma, B . F.; Boonstra, M.; Pizzi, Α.; Tekely, P.; Militz, H . 1998. Holz als Roh- und Werkstoff 1998, 56(3), 149-153. 68. Welzbacher, C. R.; Rapp, A . O. International Research Group on Wood Preservation, Doc. No. IRG/WP 02-40229, 2002. 69. Welzbacher, C. R.; Rapp, A . O. International Research Group on Wood Preservation, Doc. No. IRG/WP 04-40312, 2004. 70. Barnes, Η. M. (ed). Proceedings, Wood Protection 2006, Forest Products Society, Madison, WI (in press). 71. Hill, Callum A . S. Wood Modification: Chemical, Thermal and Other Processes. Wiley. New York, 2006. 72. Vlosky, R. P.; Shupe, T. F. Forest Product Journal 2004, 54(12), 289-295. 73. Centers for Disease Control and Prevention. U R L http://www.cdc.gov/health/mold.html 74. Amburgey, T . L . M S U Extension Forestry Technical Note, MTN-E14, Mississippi State University, 2005, 2 pp. 75. Kirkpatrick, J. W.; Barnes, Η. M. International Research Group on Wood Protection, Document No. IRG/WP 06-(in press), 2006. 76. Curling, S.F.; Carll, C. C.; Micales, J. Α.; TenWolde, Α.; Winandy, J. E.. Holzforschung 2002, 57(1), 8-12. 77. Curling, S. F.; Clausen, C. Α.; Winandy, J. E. International Biodeterioration & Biodegradation, 2002, 49, 13-19. 78. Curling, S. F.; Clausen, C. Α.; Winandy, J. E . Forest Prod. J. 2002, 52(7/8), 34-39.


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