Density profile and morphology of viscoelastic thermal compressed wood

A simple, practical, and low-technology approach was developed to fabricate corrugated bamboo particleboards (CBP), a novel bamboo product with a corrugated structure, from bamboo waste (planer waste). This product could be manufactured anywhere in the world where the bamboo industry develops. The selected mechanical and physical properties of CBP were prepared with urea formaldehyde resin at three press temperatures and two density levels and were evaluated. The results showed that the performance of CBPs is highly dependent upon the board density. The static bending strength of CBP laminated with MDF initially increases, and then decreases with increasing press temperature. Increasing the magnitude of the press temperature has a slightly positive effect on the thickness swelling and water absorption. Compared with the excellent mechanical strength of CBP (laminated with MDF), the thickness swelling value of this bamboo-based particleboard without any waterproofing treatment was lower than the minimal requirement of the EN standard.

Section: Dimensional Stabilitysupporting

confidence: 83%

Section: Dimensional Stabilitymentioning

confidence: 99%

Selected Properties of Corrugated Particleboards Made from Bamboo Waste (Phyllostachys edulis) Laminated with Medium-Density Fiberboard Panels

Feng¹,

Fei²,

Wu³

et al. 2014

“…Wood can be densified by applying a thermo-mechanical (TM) or thermo-hydromechanical (THM) treatment, or viscoelastic thermal compression (VTC) (Kutnar et al 2009), using the linear vibration friction technology (LVFT) (Rautkari et al 2009). Wood can be densified in its whole volume (Ülker et al 2012; İmirzi et al 2014) or on the surface (Belt et al 2013;Laine et al 2013b;Rautkari et al 2013;Kariz et al 2017).…”

Section: Introductionmentioning

confidence: 99%

“…It should be noted that the main problem involved in thermo-mechanical treatment of wood is a tendency for dimensions to change after the modification, most frequently referred to as "set-recovery" (Fang et al 2012;Popescu et al 2014;Laine et al 2016). Kutnar et al (2009) stated that wood with the highest degree of compression shows the highest potential for compression strain recovery. The surface densification of wood may be an alternative to the densification of the whole volume, which may contribute to a set-recovery reduction of wood.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Process Parameters on the Density Profile and Hardness of Surface-densified Birch Wood (Betula pendula Roth)

Laskowska¹

2017

This study examined the influence of temperature and time of treatment on the density profile and hardness of surface-densified birch wood (Betula pendula Roth). An analysis of the wood density profile was conducted on the basis of the following parameters: thickness, maximum density, and the distance between the maximum density and the wood surface. Depending on the technological parameters' values, the degree of compression of the wood was 13% to 22%, and its maximum density was 808 kg/m 3 to 994 kg/m 3 . As a result of the modification of birch wood at a temperature of 100 °C and 125 °C, the wood was densified on one side. As the temperature of the thermo-mechanical treatment was raised from 150 °C to 200 °C, the wood became densified on both sides. The maximum density of the wood increased gradually with the increase of the temperature of the press plate. The longer the time of thermomechanical treatment, the more distant the maximum density area was from the wood surface. Depending on the temperature and the time of treatment, the hardness of the surface-densified birch wood was 1.4 to 2.2 times greater than the hardness of non-densified wood.

“…Also, many more attempts have been made to develop a suitable process for the densification of wood including compression treatment combined with steam and heat. Usually, density enhancement is achieved through a dynamic process that combines temperature ranging from 130 to 220 °C, saturated steam, and mechanical compression perpendicular to the grain (Boonstra and Blomberg 2007;Dogu et al 2010;Fang et al 2012aFang et al , 2012bHigashihara et al 2000;Inoue et al 2008;Kutnar et al 2009;Kutnar and Kamke 2012;Wu et al 2010). Water-soluble, low molecular weight resin systems have been studied extensively and are supposed to have non-bonding cell wall swelling during impregnation processes (Inoue et al 1991a(Inoue et al , 1991bOhmae et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Study of Chemical Modification by Impregnation of Fresh Poplar Log and by Hot-Press Drying Process

Chen¹,

Qian²,

Zhang³

et al. 2013

In this work, fresh poplar logs were chemically impregnated with a pulsedipping machine. The impregnated timbers were compressed and dried by use of a multilayer hot-press drying kiln. With a compression rate of 28.67%, such an approach not only enhanced the density and mechanical properties of the treated wood, but also influenced the set recovery from the compressive deformation. Extra urea was added into the modifier to optimize the effect of the set recovery; however the result was a slight decrease in the mechanical properties. The positions of the X-ray diffraction (XRD) peaks did not change, which indicated that the structure of the cellulose was not noticeably affected by this treatment. The Fourier transform infrared spectroscopy (FT-IR) analysis showed that the intensity amide (N-C=O) absorption peak increased significantly due to the chemical impregnation. Scanning electron microscopy (SEM) showed that the high strain in the hot-press process drastically reduced the volume of void spaces in the specimens and deformed the cell lumens.