Simple and Useful Index for Analyzing Particleboard Subjected to Outdoor Exposure

摘要

Particleboards were subjected to outdoor exposure at eight sites in Japan, and the reduction in their strength (modulus of rupture and internal bond strength) was analyzed. The strength decreased with increasing thickness change as the particleboards swelled. Furthermore, the strength decreased with increasing mass loss. The correlation coefficients between thickness change and strength and between mass loss and strength were found to be strong. On the other hand, density reduced with increasing thickness change and mass loss. Since density reduction depended on both thickness change and mass loss, the correlation coefficient between density and strength was found to be the strongest. Therefore, it was concluded that density is a simpler and more useful index than thickness change and mass loss. In addition, score of the first principal component calculated by the principal component analysis of the climate factors, namely, temperature, precipitation, and sunshine duration was also found to be a simple and useful index to simplify these factors. A higher score of first principal component resulted in lower strength after the outdoor exposure test.