The mechanical properties of boards treated with vapor boron
1994
Hashim, R. | Murphy, R.J. | Dickinson, D.J. | Dinwoodie, J.M.
Several mechanical properties of medium density fiberboard (MDF), particleboard, and oriented strandboard (OSB) were investigated after the boards were treated to two retention levels of boric acid applied with a vapor-phase system. The test retentions represented levels appropriate for protection against biological attack and fire. The treatment had no significant effect on modulus of rupture (MOR), internal bond strength (IB), or bond durability in any board type when compared with untreated boards. Stiffness was increased by treatment. At fire-retardant loadings, MOR, IB, and bond durability properties were not significantly affected in any board, although in OSB and particleboard the IB strength and bond durability showed a small but statistically significant increase. Treatment reduced impact resistance by statistically significant amounts in all board types with the greatest reduction at the higher retention. In MDF, the treatment had a much greater effect on impact resistance when long treatment times were used instead of short times to achieve flame-retardant retentions. Conclusions are that vapor boron treatment resulted in either positive or neutral effects on most of the mechanical properties of wood-based boards, except for a general reduction in impact resistance at the higher boric acid retention. The possible mechanisms for these effects are discussed.
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