Pyrolysis, Leach Resistance, Hygroscopicity, and Decay Resistance of Wood Treated with Organophosphorus Esters in Combination with Isophorone Diisocyanate
Keywords:Flame retardant, Fyrol 6, Fyrol 51, organophosphorus esters, isophorone diisocyanate, wood, hygroscopicity, decay resistance
AbstractThis study evaluated the effectiveness of a difunctional isocyanate to improve the performance of organophosphorus flame retardants. Small southern pine specimens were reacted with isophorone diisocyanate in combination with two organophosphorus ester compounds. The resulting treatments were leach-resistant, not hygroscopic, and moderately decay-resistant, and had thermal degradation patterns like those of effective flame retardants. Pyrolysis of the treated specimens showed lower temperatures at the maximum rate of pyrolysis and greater amounts of residual char compared to untreated specimens. Treated specimens had 2% to 3% less equilibrium moisture content at 27 C and 80% relative humidity than did the untreated specimens. The most leach-resistant specimens lost less than 20% phosphorus during water extraction. This loss of phosphorus did not appreciably change the thermal degradation of the specimens. The treated specimens were more decay-resistant than the untreated ones.
ASTM. 1991. Standard method of testing wood preservatives by laboratory soil-block cultures. D1413-76 (reaffirmed 1986). American Society for Testing and Materials, Philadelphia, PA.nBrowne, F. L., and W. K. Tang. 1962. Thermogravimetric and differential thermal analysis of wood and of wood treated with inorganic salts during pyrolysis. Fire Research Abstract and Review, National Academy of Science, National Research Council 4(1, 2): 76-91.nEllis, W. D., and R. M. Rowell. 1984. Reaction of isocyanates with southern pine wood to improve dimensional stability and decay resistance. Wood Fiber Sci. 16(3): 349-356.nEllis, W. D., and R. M. Rowell. 1989. Fire retardant treatment of wood with a diisocyanate and an oligomer phosphonate. Wood Fiber Sci. 21(4): 367-375.nJain, R., K. Lai, and H. L. Bhatnagar. 1985. Thermal degradation of cellulose and its phosphorylated products in air and nitrogen. J. Appl. Polymer Sci. 30: 897-914.nSchuyten, H. A., J. W. Weaver, and J. D. Reid. 1955. Flame retardant paints. Indust. Eng. Chem. 47: 1433-1439.nShafizadeh, F. 1968. Pyrolysis and combustion of cellulosic materials, vol. 23. Pages 419-470 in Advances in carbohydrate chemistry. Academic Press Inc., New York, NY.nTang, W. A., and W. K. Neill. 1964. Effect of flame retardants on pyrolysis of alpha-cellulose. J. Polymer Sci. Part C (6): 65-81.n
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.