Effect of wood drying and heat modification on some physical and mechanical properties of radiata pine

ABSTRACT

To evaluate evolution of physical and mechanical properties due to drying and heat modification, a load of radiata pine wood was selected and properties were measured after each drying process. The results revealed interesting correlations between intrinsic factors and properties; the values of density were highly dispersed after drying or thermal treatment and uncorrelated with other parameters, but the minimum density values were kept constant after heat treatment. Moreover, weight loss (WL) and moisture content (MC) were decreasing proportionally to the treatment intensity, due to wood–water interactions, cell wall changes, and thermal degradation of wood fractions. WL and MC were reasonably correlated with the dimensional stability, improving the dimensional stability after drying treatments, but keeping the same order of anisotropy. Regarding the wood stiffness (modulus of elasticity, MOE), it was unaffected by the drying temperature, and the correlations between MOE and MC or WL appear to be acceptable, and the values of MC or WL did not adversely affect the MOE. However, the modulus of rupture was dropped during the drying process, obtaining three differentiated groups with a decrease in around 59% after thermal modification.

KEYWORDS:

• Heat-treatment
• high-temperature drying
• kiln-drying
• thermal modification
• wood drying

Additional information

Funding

The authors appreciate the financial support of the National Commission of Scientific & Technological Research (Conicyt) of Chile (Fondequip EQM130236), the Basque Government (scholarship of young researchers training, IT1008-16) and the support of COST Action FP1407 through STSM-35419.