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VOLUME 60, ISSUE 1/2019

Static-dynamic component analysis by load-increasing tests using the example of a load-handling device in wood construction; Part 1: Calculation of components made of wood veneer composites

Language: German
Pages: 15 - 22
Authors: Patrick Kluge, Sven Eichhorn, Eric Penno

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Wood is not in common use as a construction material for applications in mechanical and plant engineering. Anisotropic mechanical properties with high scattering coupled with many factors influencing the mechanical behaviour make it difficult to calculate components made of WVC (wood veneer composites). Using the example of a load-carrying device in the form of a cross-beam in timber construction, calculations were carried out with known formulas of technical mechanics and the Eurocode 5. The results of the calculation are presented in this first part of the article and compared and evaluated with values determined in laboratory tests.

On the release of formaldehyde from particleboards and fibreboards using urea as a scavenger; Part 2: Influence on the mechanical-physical behaviour of particleboards and fibreboards

Language: German
Pages: 23 - 31
Authors: Almut Wiltner, Andreas Weber

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One E1 reference resin was modified by urea solution. The influence of this urea aolution on the mechanical-physical values of particleboards and fibreboards was estimated. In the case of particleboards, a direct dependency between lowered reactivity of such modified E1 resins with urea addition and tensile strength values as well as swelling behaviour could be observed. The raw density as well as their profile were not influenced by additional urea. The fibreboards were processed using blowline technique. The urea solution was added to the E1 resin and the mixture was applied in the blowline. In comparison to that the urea addition was done separately on the wood chips, in the blowline (before and after resin addition) and finally, directly to the dryer. Moreover, a second type of fibreboards was processed by varying the raw density as well their profile. From these measurements and the estimated values, again, the lowered reactivity of the modified E1 resin can be obtained. The order of urea addition is insignificant.

Wood composites for future automotive engineering? Basic requirement: crash simulation of wood-based components

Language: English
Pages: 5 - 14
Authors: Ulrich Müller, Florian Feist, Thomas Jost

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Wood provides high stiffness, strength, excellent damping, high resistance against fatigue and a very low density paired with low material costs. Properly applied, modern wood composites are competitive to metals and fibre-reinforced polymers. However, the application of wood and wood composites in automotive engineering requires precise and reliable material data, e. g. for a very first material selection and later in numerical crash simulations. A feasibility study was performed, that identifies the potential of explicit finite element (FE) simulation of wood and wood products under static and crash load condition. Consequently, future necessary development tasks for further improve of wood related FE simulation were derived.

Hydrodeoxygenation of lignin-derived residues for the production of intermediates for the FCC-process

Language: German
Pages: 32 - 40
Authors: Jörn Appelt, Jan Ole Strüven, Patrick Eidam, Dietrich Meier

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In the course of substitution of crude oil derived valuable substances, lignocellulosic feedstocks were made available by different research activities in the past. Thereby biogenic intermediates should be integrated into conventional petrochemical processes. Hydrothermal conversion in subcritical liquid phase and hydrodeoxygenation are suitable processes for the conversion of black liquor to compatible intermediates used for classical petrochemical pathways. However, the conversion needs multi-step processes for deoxygenation and upgrading to valuable intermediates. The hydrodeoxygenation of a HTL-product from black liquor was studied within an international project at the Thünen Institute of Wood Research Hamburg, Germany. The effects of key parameters on the hydrodeoxygenation such as reaction temperature, pH-value and bimetallic zeolite catalysts have been investigated. A high degree of deoxygenation and high amounts of monomeric products were observed at temperatures around 380 °C. An alternative concept for catalytic conversion in subcritical liquid phase could be tested successfully as well. Valuable products from both conversion processes can be integrated to conventional petrochemical pathways without additional efforts.

Montan wax containing additives – a new generation of highly efficient water-repellent agents

Language: German
Pages: 41 - 45
Authors: Carola Tretner,, Jörg Abraham, Andreas Mieth, Henry Burkhardt

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Montan wax based dispersions established for the hydrophobization of mineral building materials (trade name: MONTAX) were optimized and evaluated for the application fi eld of wood-based materials. In the present work, the investigations carried out within the framework of an IGF project on the manufacturability of HDF using these montan wax containing dispersions are outlined as additives and the fundamental fi ndings obtained are presented using the example of MONTAX 55. It has been found that the use of MONTAX 55 makes it possible to produce high density fibreboards with industrially analogous properties and that it has an excellent hydrophobizing effect with regard to thickness and edge swelling, whereby the transverse tensile strength is even positively infl uenced. This behaviour suggests additional binder assisting effects when using montan wax in additives for hydrophobization.

Rapid testing suitable for factory production control of volatile organic compounds (VOC) released from wood based panels

Language: German
Pages: 46 - 51
Authors: Jörg Hasener, Vera Steckel

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The release of volatile organic compounds (VOC) from building products will be regulated in a significantly more comprehensive way than in the past. DIN EN 16516 (2018) serves as the basis by presenting harmonized testing procedures. In consequence, CE-marking of the VOC release will be required, and, for many products, factory production control will be necessary. However, the proposed methods are not suitable for application in factory labs because they are elaborate and need to be operated by highly specialized personnel. This article is about a new, robust rapid testing method that uses a gas analysis system (cf. DIN EN ISO 12460-3, 2016) to enable the release of VOC from specimens in a controlled environment. The emitted compounds are enriched and then transferred into the analytical system consisting of a gas chromatograph to separate them and, coupled to it, an ion mobility spectrometer to perform the quantitative determination. In this article, the new rapid testing system, first results, and the regulatory situation are presented.

Separation, modification and possible use of hemicelluloses and pectin based on agricultural residues

Language: German
Pages: 52 - 58
Authors: Stefan Gebke, Katrin Thümmler, Steffen Fischer, Martin Kahl, Ines Aubel, Martin Bertau

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At the Institute of Plant and Wood Chemistry of the Technische Universität Dresden methods of separation and modification of hemicelluloses based on agricultural residues (oat husks, wheat straw and sugar beet pulp) are developed. The used alkaline pulping process is sulphur-free. Hemicellulose is separated from black liquor using ultrafiltration and nanofiltration. In parallel, the delignification of residues using hydrogen peroxide is investigated. Characterisation and valuation of the products occurs in cooperation with the Institute of Technical Chemistry of the Bergakademie Freiberg. The chemical composition and the molar mass and their distribution are in the foreground of these investigations. The hemicelluloses are optimized and modified with regard to possible applications. Positive results are obtained for using hemicellulose as additive for flotation processes and for using modified hemicelluloses as flame retardants.

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