WOOD RESEARCH Volume 69, Number 1, 2024
VLADIMÍR IHNÁT, HENRICH LÜBKE, RASTISLAV ČEREŠŇA, JOZEF BALBERČÁK, VLADIMÍR KUŇA, ANDREJ PAŽITNÝ, and ŠTEFAN BOHÁČEK

THIN LIGNOCELLULOSIC LINERS BASED OF SPRUCE SHAVINGS

The article is devoted to determining the basic physical and mechanical properties of sheet materials up to 1.5 mm thick based on wood shavings and PVAc glue with a high proportion of water, pressed under high pressure up to 25 MPa and a temperature of around 190°C, so that the softening of lignin caused by the generated steam, allow to create a compact and non-crumbling surface. In order to characterize the physical-mechanical properties of the new wood-based sheet material with minimum thickness and characteristic elasticity, tests according to the CEPI (Confederation of European Paper Industries) standards were adopted. Procedures for tensile strength according to ISO 1924-2 (2008), Burst strength according to ISO 2758 (2014), puncture according to ASTM D781-68 (1973), water absorption according to ISO 5637 (1989) and porosity according to TAPPI Test method T460 were applied

WOOD RESEARCH Volume 65, Number 6, 2020
Jiulong Xie, Lin Chen, Huijuan Shao, Lu He, Yongze Jiang, Dan Lu, Hui Xiao, Yuzhu Chen, Xingyan Huang, Jianfeng Hao, Lihua Tu, Tiantian Lin, Yinlong Xiao, Gang Chen, and Jinqiu Qi

Changes in physical-mechanical properties and chemical compositions of Toona sinensis wood before and after thermal treatment

Vacuum heat treatment was used to improve the dimensional stability of Toona sinensis wood in this study, the shrinking and swelling rates, the physical-mechanical properties, and the chemical compositions before and after the thermal treatment were evaluated. The results revealed that the volume shrinkage and swelling rate for the heat-treated wood samples were decreased by 45.60% and 49.95%, respectively at 220°C for 6 h indicating that thermal treatment could obviously improve the dimensional stability of Toona sinensis wood. Thermal treatment also decreased the mechanical strength. The surface color was changed by the treatment. The chemical composition results showed the decrease in density and mechanical strength was due to the partial degradation of hemicellulose during the treatment. The results of this study that vacuum heat treatment could improve the dimensional stability by sacrificing somewhat mechanical strength, the treatment conditions mainly the temperature should be properly controlled to archive an optimized improvement in dimensional stability with minimum reduction in mechanical strength.

WOOD RESEARCH Volume 65, Number 4, 2020
Laércio Serenini Jr., Rafael Rodolfo De Melo, Diego Martins Stangerlin, and Alexandre Santos Pimenta

Wood quality of six eucalyptus clones planted in northern Mato Grosso State, Brazil

The present work had the goal of assessing the wood quality through physical-mechanical properties of six 5-year old eucalyptus clones currently planted in northern Mato Grosso State, Brazil. The following clones were assessed, five of them Eucalyptus grandis x Eucalyptus urophylla hybrids and one a clone of Eucalyptus camaldulensis. The physical-mechanical properties were basic density as a function of tree height; pith-to-bark direction; linear, tangential and radial shrinkage; and anisotropic coefficient, longitudinal and parallel compression and static bending strengths; and hardness. Eucalyptus grandis x Eucalyptus urophylla hybrids showed the best wood quality. Concerning to mechanical results, the clones reached intermediate values of strength and rigidity, qualifying them for use in structural applications with less stringent requirements. Considering that all the clones had juvenile wood, the mechanical properties were satisfactory, making the clones suitable for industrial uses.