INFLUENCE OF TIME AND HEAT TREATMENT TEMPERATURE ON PERMEABILITY OF <i>Eucalyptus grandis</i> WOOD

Freitas, Fabiana Paiva de; Carvalho, Ana Márcia Macedo Ladeira; Carneiro, Angélica de Cássia Oliveira; Vital, Benedito Rocha; Gonçalves, Lira Maria Sivieiro; Jesus, Márcia Silva de; Xisto, Mariana Fonseca

doi:10.1590/1806-90882019000300001

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Article • Rev. Árvore 43 (3) • 2019 • https://doi.org/10.1590/1806-90882019000300001 copy

INFLUENCE OF TIME AND HEAT TREATMENT TEMPERATURE ON PERMEABILITY OF Eucalyptus grandis WOOD

INFLUÊNCIA DO TEMPO E DA TEMPERATURA DE TRATAMENTO TÉRMICO NA PERMEABILIDADE DA MADEIRA DE Eucalyptus grandis

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

Due to the fact that raw timber has permeability characteristics unsuitable for some applications, several processing techniques have been developed, such as hydrothermal treatments and freezing, which aim to improve these properties. The objective of this study was to analyze the effects of treatment temperature and duration on the permeability of Eucalyptus grandis wood. Heartwood samples from three E. grandis trees were utilized, each with the dimensions 30 x 8 x 3 (length, width, thickness). The treatments were carried out at three temperatures (-20°C, 60°C, and 100°C) and three exposure durations (5, 10, and 15 hours). Treatments at -20°C were conducted inside a domestic freezer, while treatments at 60°C and 100°C took place inside a Parr Reactor, while the wood being submerged in water. Extractive removal was only observed at the surface and interior of wood treated at 60°C and 100°C; while all treatment conditions increased permeability with respect to control treatments.

Keywords:
Freezing; Hydrothermal; Chemical composition

Table 1 Experimental design

Treatments	Conditions
Treatments	Temperature (°C)	Time (h)
1	-20	5
1	-20	10
1	-20	15
2	60	5
2	60	10
2	60	15
3	100	5
3	100	10
3	100	15
Witness	23	-

Table 2 Mean values of extractives (%) of the surface of Eucalyptus grandis wood acoording to the treatments

Temperature	Time (hours)			Average
(°C)	5	10	15
-20	Aa 6.34 ^ns n.s indicate no significant differences and	Aa 6.23 ^ns n.s indicate no significant differences and	Aa 6.77 ^ns n.s indicate no significant differences and	6.44
60	4.33 Ba ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level).	4.35 ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level). Ba	4.27 ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level). Ba	4.31
100	3.57 Cab ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level).	3.24 ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level). Cb	3.67 ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level). Ca	3.50
Average	4.75	4.60	4.90
Witness	6.65

Table 3 Mean values of holocelulose content (%) of the surface of Eucalyptus grandis wood according to the treatments

Temperature	Time (hours)			Average
(°C)	5	10	15
-20	Aa 62.84 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	Aa 61.84 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	Aa 62.89 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	62.52
60	Aa 63.20 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	Aa 64.35 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	Aa 65.21 *	64.25
100	Aa 65.56 *	Aa 63.95 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	Aa 63.23 ^ns n.s indicate no significant differences between the means and the control by Dunnett test (all at 95% probability level).	64.24
Average	63.86	63.38	63.77
Witness	61.64

Table 4 Mean values of the extractives content (%) of the inner timber of Eucalyptus grandis wood according to the treatments.

Temperature	Time (Hours)			Average
(°C)	5	10	15
-20	5.36 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	5.54 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	5.55 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	5.48 A
60	5.14 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	5.97 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	5.11 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	5.41 A
100	4.68 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	4.70 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	4.32 ^ns n.s indicates non-significant differences between the means and the control by the Dunnett test (all at the 95% probability level).	4.57 B
Average	5.06	5.40	4.99
Witness	5.32

Table 5 Mean permeability values (cm2.atm-1.s-1) of Eucalyptus grandis wood according to the treatments.

Temperature	Time (hours)			Average
(°C)	5	10	15
-20	9.89 ^ns n.s indicates no significant differences and	8.44 ^ns n.s indicates no significant differences and	11.70 ^ns n.s indicates no significant differences and	10.01 B
60	8.82 ^ns n.s indicates no significant differences and	7.97 ^ns n.s indicates no significant differences and	10.36 ^ns n.s indicates no significant differences and	9.05 B
100	9.37 ^ns n.s indicates no significant differences and	15.80 ^ns n.s indicates no significant differences and	22.69 ^* * indicate significant differences between the means and the control by Dunnett test (all at 95% probability level).	15.96 A
Average	9.36 b	10.74 ab	14.92 a
Witness	7.78

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