Flame-Retardant Treatment Of Wood With A Diisocyanate and An Oligomer Phosphonate
Keywords:
Flame retardant, phosphonate, diisocyanate, pyrolysis, thermogravimetry, thermal degradationAbstract
An oligomer phosphonate and isophorone diisocyanate, in a chloroform or dichloromethane solution, were impregnated into wood and cured at 105 C. The leach resistance and thermal degradation of treated wood specimens were evaluated. Leaching milled specimens removed up to 49% of the phosphorus and 12% of the nitrogen. The average weight percent gain of solid specimens leached with three 4-day cycles of running water was reduced from 23% to 17% during the first cycle and from 17% to 16% during the second and third cycles. Toluene: ethanol extraction did not remove the reacted chemicals from the wood. Acetone extraction resulted in a 1% to 2% reduction of the weight percent gain values. Thermal analysis showed that the flame-retardant treatment reduced the temperature at maximum rate of pyrolysis approximately 80 C and increased the amount of residual char to about 30%. Leaching raised the temperature on the average 8 C at the maximum rate of pyrolysis and decreased the amount of residual char an average of 3%. The temperature at maximum rate of pyrolysis and amount of residual char indicate the potential effectiveness of this treatment as a leach-resistant, flame-retardant treatment for wood.References
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