ABSTRACT:The objective of this research was to improve the fire-retardant properties of wood in one treatment using a phosphorus pentoxide-amine system. Phosphorus pentoxide and 16 amines including alkyl, halophenyl, and phenyl amines were compounded in N,N-dimethylformamide and the resulting solutions containing phosphoramides were reacted with wood. The characteristics of phosphoramidereacted wood were analyzed by FTIR, energy-dispersive X-ray analysis, and elemental analysis. Fire retardancy of phosphoramide-reacted woods was evaluated by DSC and thermogravimetric analysis (TGA). DSC demonstrated that the modification can lower the onset of an endotherm and decrease the heat of combustion and heat flow. TGA showed that most of the phosphoramide-reacted woods had higher char yields than that of wood impregnated with diammonium phosphate.

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Wood coatings of PU-NC semi-interpenetrating polymer networks (semi-IPNs), made from blown castor oil (BCO), aromatic polyisocyanate (PTDI), and nitrocellulose (NC) , were prepared by sequential polymerization method. To investigate the effects of NC on the properties of PU-NC semi-IPNs wood coatings, three different viscosities of NC ( 1 2 -sec, -sec NC, the addition of 0.2% DBTDL could effectively reduce the drying time of the coating and improve the film properties, including tensile strength, elongation at break, and lightfastness. In addition, the miscibility of PU and NC was examined in PU-NC semi-IPNs with 1 4 -sec NC.

Resistance of wood reacted in situ with phosphorus pentoxide-amine to the brown-rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolor was examined. Wood reacted with either octyl, tribromo, or nitro derivatives were more resistant to both fungi. Threshold retention values of phosphoramide-reacted wood to white-rot fungus T. versicolor ranged from 2.9 to 13.3 mmol, while these for brown-rot fungus G. trabeum ranged from 8.1 to 19.2 mmol. Wood reacted with phosphoramide tested to be more resistant to white-rot than brown-rot attack.