Residues of Bagasse (Saccharum officinarum L.), canola (Brassica napus L.) and hemp (Cannabis sativa L.) as well as industrial wood chips in various proportions from 0-100% were used as raw materials for the main component of the middle layer in urea formaldehyde bonded particle boards.The results reveal that most of the investigated mechanical-technological properties of the boards achieved the requirements of EN 312-2 (2003). Only increasing the percentage of canola chips usage in the middle layer to more than 30% negatively affect the internal bond (IB) properties. Comparing the water absorption (WA) and thickness swelling (TS) values, the boards containing up to 50% bagasse and hemp reach similar values to the ones of the reference boards, while increasing the amount of canola leads to more and more disadvantageous WA and TS.In summary, the results reveal that agri-fibers can be used for making composite panels conforming to the standards (EN 312-2 2003). One possible application for these panels could be the production of furniture. Einsatz von Ernterückständen von Bagasse, Rapsstroh und Hanfschäben bei der Herstellung von dreischichtigen SpanplattenThis article is dedicated to Gerd Wegener on the occasion of his retirement as professor at the Technische Universität München.

This article deals with the feasibility of the use of wheat protein glue to produce general purpose particleboards from bagasse, canola, and hemp chips and of decreasing the formaldehyde emission by using a bioproduct adhesive. Three series of panels were produced using wood chips in the surface layers and a mixture of annual plants with industrial wood in the middle layers. Particleboards were manufactured using various annual plants. Wheat protein was used in combination with urea-formaldehyde (UF) resin in the surface layers. Pure UF was only used in the middle layer. Panels were tested for some physical and mechanical properties. In addition, the formaldehyde emission according to the perforator method and the bottle method was determined. The data were compared with the respective properties specified by the Deutsches Institut für Normung EN 312-2 standard for commercial wood-based particleboard. The results showed that all mechanical properties greatly exceeded the standard requirements for wood particleboards. An increase of more than 50 percent canola particles in the core negatively affected the internal bond (IB) strength. All of the particleboards produced from hemp and bagasse had modulus of rupture and IB strength higher than required. With those containing up to 50 percent annual plant particles in the middle layer, thickness swelling values met the standard requirement. It was found that applying wheat protein as a bonding agent reduced the formaldehyde emission in comparison to when pure UF resin was applied. This study demonstrated that consistent, high-performance agricultural fiber composite panels with desirable environmental attributes can be successfully developed.

This work was focused on the production and characterization of lightweight and water resistance particle boards with various lignocellulosic materials of the annual plants hemp (Cannabis sativa L.), canola (Brassica napus L.) and bagasse (Saccharum officinarum L.) in admixtures with industrial wood. Some chemical properties of these annual plants were investigated to find out their chemical characteristics in wood composites production. In all board variants 100% of the middle layers consisted of chips from one of the above annual plants. Reference boards were 100% beech wood. Laboratory manufacturing treatments included two panel density levels (500 and 600 kg/m 3 ) and three resin types (urea-formaldehyde, melamine-urea-formaldehyde and wheat protein).Water absorption and thickness swelling of the laboratory manufactured boards were improved by adding melamine to urea-formaldehyde resin and by adding water repellent chemicals. The mechanical properties of the boards produced met the requirement for the general purpose product standards (EN 312-2) at both 500-and 600-kg/m 3 densities. Decreasing the density, negatively affected the bending (modulus of rupture) and internal bond properties of canola boards. This decreasing trend was also observed for modulus of rupture values in bagasse boards of 500 kg/m 3 density.Based on the results of the chemical analysis, it might be concluded that high values of ash content and lower values of hemicellulose and lignin content caused low physical properties and/or high water absorption of canola boards. The findings indicated that hemp and bagasse are valuable renewable natural resources for particleboard production and could be utilized as a substitute for wood in board production. In comparison with the reference boards, mixed variants boards showed surprisingly good results and generally conformed to European standards (EN 312-2) values.