Correlation between natural and artificial aging in particleboards

Resumo

The main objective of this work was stabilizing correlation between natural aging with artificial aging in medium density particleboards produced with polyurethane resin of castor oil and Pinus sp. It was done using climatological parameters at São Carlos city, Brazil and a calculation methodology. And it was calculated that 20 cycles would be proportional the same degradation of two months of exposition of natural aging. There was reduction in the mechanical properties over time for weathering. The relation between physical and mechanical properties with the effects provide by number of months (M) in the natural aging with number of cycles (Nc) in the artificial aging was obtained with cubical polynomial regression models. In general, for physical properties 20 Nc are around at 7 and 8 months, and for mechanical properties are around at 11 and 12 months, with exception internal bonding with 8 months. The expectative with the calculation was 20 Nc is the same two months of outdoor exposition. The equations that best represent relation between Nc and M were thickness swelling at 2h and water absorption at 2 h and 24 h, with R² larger 93%.