Brittleness increase in Eucalyptus wood after thermal treatment

ABSTRACT

Thermal treatments arise as an alternative to increase the physical and biological properties of wood, though they usually cause a reduction in mechanical strength. Therefore, the aim of the study was to determine the brittleness of Eucalyptus wood submitted to freezing and heat treatments. Freezing occurred with green condition specimens and the heat treatment with samples in equilibrium moisture content (20°C and 65% RH). The static bending test was carried out on an EMIC® universal testing machine. The freezing showed slight changes in the mechanical properties of Eucalyptus wood, not differing from natural wood. The treatments with high temperatures caused significant losses in mechanical strength, evidenced by decreases in maximum load and increases in brittleness. In the combined treatments, there was no sum of effects. Therefore, heat treatments modify the mechanical properties of wood, increasing its brittleness and following the tendency that, as the temperature increases, the mechanical resistance decreases.

KEYWORDS:

• Mechanical properties
• wood quality
• thermo modification

Acknowledgement

The authors wish to thank Miss Bia Carneiro for the English revision of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

ORCID

Henrique W. Dalla Costa http://orcid.org/0000-0002-2770-9453

Rodrigo Coldebella http://orcid.org/0000-0002-7063-1874

Fernanda R. Andrade http://orcid.org/0000-0002-1996-5801

Marina Gentil http://orcid.org/0000-0003-4621-1711

Ronan Correa http://orcid.org/0000-0003-3989-9271

Darci A. Gatto http://orcid.org/0000-0002-6805-3243

André L. Missio http://orcid.org/0000-0001-9373-6313

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico [grant number 155291/2018-1] and CAPES (Coordination of Superior Level Staff Improvement).