This study determined the factors influencing the boron content after leaching of pine blocks impregnated with aqueous solution of phenol-formaldehyde (PF) resin with or without borax and subjected to heat treatment by response surface methodology. An experimental design permits to analyze the effects of heat treatment temperature (150, 185 and 220°C), curing time (5, 12, 5 and 20 hours), resin concentration (5, 12.5, and 20%) and boron concentration BAE (0, 2, and 4 %) on the mass gain, boron content as well as degradability. After leaching, the treated samples with 20% PF, and 220°C had high boron content, and the heating time had no significant influence on the boron content. Decay and termite resistance were also studied for treatments involving impregnation of samples with 10% of PF alone or in the presence of borax, followed by curing at 220°C for 5 h. The results of this study indicated that the decay and termite resistance of all samples pretreated and leached is sufficient to envisage use in outdoor exposure.

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