VOLUME 53, ISSUE 5/2012

Acacia mangium is a fast-growing wood that is used in Vietnam more and more for different purposes. In the context of investigations Acacia mangium from Vietnam was thermally modified to improve its dimensional stability and durability. The thermal modification leads to many changes of properties such as the mass, the colour, the equilibrium moisture content, the density and porosity as well as bending and compression strength. This paper describes these changes and the relations between them and the modification conditions.

Currently available particle boards for furniture industry and interior outfitting with a density of more than 630 kg/m³ are too heavy for different applications. Therefore, the reduction of the density of particle boards by use of various light-weight fillers up to a range of 450 to 500 kg/m³ was investigated. Inorganic as well as organic filler materials were used in the middle layer to manufacture three-layered particle boards with densities in the area of 400 to 600 kg/m³ and thicknesses of 30 mm. The attained panel properties were compared to the requirements, as given in DIN EN 312 (2010), of particle boards of the P2-type – boards for interior fitments, including furniture, for use in dry conditions. Amongst others, positive results could be reached with extruded polystyrene, cork granules and expandable unexpanded polystyrene. The requirements concerning internal bond strength and thickness swell as for the P3-type could be met - with regard to bending properties partly not. Part 1 of this publication shows the current situation of lightweight panels as well as material and methods of experimentation. Part 2 will show selected results.

Considerable quantities of bark accrue as a by-product of the timber harvest in Germany every year. These barks are currently mostly utilized for energy production or soil additives. However, the increasing scarcity of wood raw materials and required reduction of formaldehyde release in particle board manufacturing give rise to determine the usage of bark in particle boards systematically. This first part shows the influence of bark from spruce, pine, beech and oak on the physical and technological properties of three-layer particle boards. The results vary depending on the origin of the studied bark. However, the experiments revealed that using about 20 % of bark derived from spruce in particle board production has no negative effect on the mechanical properties of particle boards in comparison to boards manufactured without bark. In a following second part we will show the results of studying the formaldehyde emissions of particle boards containing bark.

For the practical rheological characterization of extruded woodpolymer composites (WPC), a bypass rheometer tool was developed, which was adapted to a twin-screw extrusion system for fibre composites. The setup allows the investigation of process rheology of highly filled WPC formulations with 50 to 80 % wood content under realistic processing conditions. It was found that the wood content has a great influence on the process rheology of the wood-polypropylene composites. The influence of additives on the melt rheology of WPC was also investigated. Furthermore, it was found that rheological parameters of the WPC melt have a direct influence on processing properties during extrusion as well as on the mechanical properties of the composites.

In the present study different nanocomposite ceramic blades were produced. Independent of material systems used, first cutting trials were successfully carried out. Due to the relatively low hardness abrasive wear was visible in ZTA blades but lifetime could be increased clearly with ACY cutting blades. Up to now commercially available cemented carbide blades still outmatch lifetime of first ceramic test blades. A developed post-lapping process has shown accurate and reproducible micro-geometries at the crack tip, which stabilizes the cutting wedge and shows potential of future ceramic cutting tools.

The calorific value of the tested wood varies in a range of 2 MJ/kg. The heating value is more strongly determined by the chemical and anatomical characteristics of the wood species than the conditions of the origin. A higher density can not, as claimed in some literature, automatically cause a higher calorific value. The chemical composition (ratio of lignin to cellulose), the content of combustible accessory constituents (fats, resin) and the proportion of non-combustible constituents (ash) are important factors affecting the heating value. In addition, the calorific value depends strongly on the moisture content. The conifers are consistently higher calorific value than hardwoods of the temperate zone. Ring-porous woods have a significantly low calorific value.

In dieser Arbeit wurde die Sub-Mikrometer-Computertomografie (sub-μm-CT) bei der Untersuchung der Struktur von OSB und Spanplatte eingesetzt. Die erhaltenen Daten wurden mit Hilfe der mathematischen Morphologie sowie der Bildanalyse aufbereitet, um Informationen über die Porengrößenverteilung zu erhalten. Die ermittelten Verteilungen entsprechen einer Γ-Verteilung. Zwischen dem mittleren Porendurchmesser und der lokalen Dichte in kleinen Subvolumina bestehen Korrelationen; im Falle der OSB sind sie wegen der inhomogenen Struktur nur schwach ausgeprägt; für die untersuchte Spanplattenprobe ist die Korrelation deutlich besser und vergleichbar zu MDF

The most effective production technology for the processing of small diameter hardwoods has been discussed for a long time in research and industry. Currently these resources are mainly used for firewood. An increase of the added value is expected by using small diameter hardwoods for material applications. Higher prizes of the logs are of high importance for a sound forestry management and the biodiversity of the forests. Therefore the development of new products, alternative production technologies and new sales possibilities of this specific assortment is of high economic interest. One major factor in this process chain are the production cost in the sawmill. This cost varies, depending on the technology which is chosen. In part 1 of this publication, the yield of processing low diameter hardwood is calculated for the species sycamore, European beech, ash and European white oak. Following on that a comparison of various cutting technologies for the processing of small diameter hardwood is presented and discussed.

Terms, such as brand, label, quality, test and certification, in combination with furniture provoke certain expectations. Brand quality is a term, which is related with a high expectation, and creation of value can be expected. The fulfilment of expectations is measured by customers who more and more consider concrete promises made by the marketing for furniture. Also in the furniture business, distance selling (via internet) will become increasingly important. The internet will continue to support the critical examination of brand statements. Independent third parties will support trust in quality statements of brands. Labels of test and certifications bodies shall document the reliability and independence of the assessments