Effects of Thermo-Vibro-Mechanic® densification on the density and swelling of pre-treated Uludağ fir and black poplar wood

Abstract

The radial and tangential swelling as well as the fully dried density of low-density wood materials densified via the Thermo-Vibro-Mechanic® method were evaluated in response to applying wood stain and preservative. The samples obtained from Uludağ fir (Abies bornmüelleriana Mattf.) and black poplar (Populus nigra L.) in the radial and tangential direction were pre-treated with wood stain and preservative before undergoing Thermo-Vibro-Mechanic® densification. Thermo-Vibro-Mechanic® densification was performed at three different temperatures (100 °C ± 3 °C, 120 °C ± 3 °C, and 140 °C ± 3 °C), three different vibration pressures (0.60 MPa, 1.00 MPa, and 1.40 MPa), and three different vibration times (20 s, 60 s, and 100 s). Afterwards, changes in the fully dried density and swelling amounts in the radial and tangential directions of the samples were determined. The fully dried density increased by 15.4% to 38% and the radial and tangential swelling amounts increased by 73.2% to 242.6%, when the densified samples were compared to the control samples. In general, the fully dried density and swelling values increased depending on the Thermo-Vibro-Mechanic® densification parameters; higher values were found as the compression ratio and total application time increased.

Influence of thermal pretreatments on dimensional change and humidity sensitivity of densified spruce and poplar wood

“…Also, thickness swelling increased with increasing compression ratio in all densified specimens (Figure 5). These determined results are compatible with the findings of previous studies (Cai et al 2013, Pelit et al 2016, Pelit and Emiroglu 2020, Budakçı et al 2021. It is known that the compressed wood tends to revert to its initial dimensions before compression under high humidity conditions or in contact with water.…”

Thermo-Vibro-Mechanic® (TVM) wood densification method: Mechanical properties

“…This method can be described as a surface densification method since it is especially effective on the outer parts of the wood. It was also reported that there was a serious change in the surface properties of the materials condensed with TVM, including its density, hardness, glossiness, abrasion, and swelling resistance (Şenol and Budakçı 2016;Şenol et al 2017;Budakçı et al 2021). In this study, the bending strength (BS), modulus of elasticity (MOE), and compression strength (CS) in the direction parallel to the fiber of Uludağ fir and black poplar specimens densified in the radial and tangential directions via the TVM method were investigated.…”