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Browsing by Author "Calonego, Fred Willians"

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    Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood
    Durgante Severo, Elias Taylor; Calonego, Fred Willians; Sansigolo, Claudio Angeli; Bond, Brian H. (PLOS, 2016-03-17)
    In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood.
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    Physical Properties of Thermally Modified Juvenile and Mature Wood of Heveabrasiliensis (Euphorbiaceae)
    Calonego, Fred Willians; Durgante Severo, Elias Taylor; Latorraca, João Vicente de Figueiredo D. F.; Bond, Brian H. (2020-05)
    Exposing timber to temperatures approaching 200 °C causes thermal modification and changes its characteristics. This study evaluates the effect of various levels of thermal treatment on the physical properties of juvenile and mature wood from rubber tree (Hevea brasiliensis). Boards taken from 53-year-old rubber trees were thermally modified at up to 220 °C. Thermal treatment caused decreases on the oven-dried density, equilibrium moisture content, and swellings on juvenile and mature woods of H. brasiliensis. Influence of thermal modification at 180- 200 °C in juvenile wood was lower than in mature wood, whereas the treatment at 220 °C caused a greater variation in properties of juvenile wood. The thermally modified wood is a suitable product for use in environments with high levels of relative humidity.