Colour responses of Eucalyptus grandis wood to the Brazilian process of thermal modification

• Published in: Maderas Vol. 20; no. ahead; pp. 661 - 670
• Main Authors: Griebeler, Carolina Gomes de Oliveira, Matos, Jorge Luis Monteiro de, Muniz, Graciela Ines Bolzón de, Nisgoski, Silvana, Batista, Djeison Cesar, Rodríguez, Carmen Iglesias
• Format: Journal Article
• Language: English
• Published: Universidad del Bío-Bío 01-10-2018
• Subjects: Colorimetry; eucalypt wood; heat treatment; MATERIALS SCIENCE, PAPER & WOOD; VAP HolzSysteme; wood grading; VAP HolzSysteme; Colorimetry; heat treatment; eucalypt wood; wood grading
• ISSN: 0718-221X; 0717-3644; 0718-221X
• DOI: 10.4067/S0718-221X2018005041201

A study of colour assessment, using the CIEL*a*b* system, was conducted with samples of Eucalyptus grandis wood thermally treated by the Brazilian industrial process of thermal modification, VAP HolzSysteme®, at three different temperatures, i.e. 140, 160 and 180 °C. Previous to the treatment, the samples were classified into three groups according to their distance to the wood pith, on the radial direction. All thermally modified samples presented a noticeable colour change, confirmed by high values of ΔE*. As the intensity of the treatment increased, the eucalypt samples presented an increase of red colour tone (a*) (up to 160 ºC) and a decrease of colour lightness (L*). Significant colour differences were found among the classified groups, for both untreated and thermally modified samples. The eucalypt samples groups showed different colour responses when thermally treated at 140 and 160 ºC. At 180 ºC the groups didn’t show a significant colour response variation.