PEER-REVIEWED ARTICLE bioresources.com Hýsek et al. (2018). “Rapeseed stalk particleboard,” BioResources 13(3), 6396-6408. 6396 Physical and Mechanical Properties of Boards Made from Modified Rapeseed Straw Particles Štěpán Hýsek, a, * Adam Sikora, b Ondřej Schönfelder, b and Martin Böhm a Composites made from annual plants, such as winter rapeseed, can be used as an alternative to wood-based composites because of their ecological character, low price, as well as physical and mechanical properties. The goal of this study was to prepare such boards and evaluate their properties. Unmodified material and chemically and hydrothermally modified rapeseed particles glued by powder polyester glue were used. The characteristics measured were the internal bonding, swelling and moisture uptake over time, and surface soundness. The results showed that modification of the raw material influenced the properties of the resulting composites. The highest swelling values were exhibited by the boards with particles that were alkaline-modified. Boards made from hydrothermally modified particles achieved the highest strengths compared with the commercially produced boards. The alkaline modification of the particles resulted in a stronger adhesive bond between the particle and adhesive. During the internal bonding test, the boards made from the alkaline-modified particles exhibited cohesive failures in the particles. Therefore, the modification of the particles increased the mechanical properties of the boards, but the physical properties deteriorated. Keywords: Rapeseed; Particleboard; Internal bonding; Surface soundness; Non-recoverable thickness changes; Thickness swelling Contact information: a: Department of Wood Products and Constructions, Faculty of Forestry and Wood Sciences, The Czech University of Life Sciences Prague, Kamycka 129, Prague 165 21, Czech Republic; b: Department of Wood Processing, Faculty of Forestry and Wood Sciences, The Czech University of Life Sciences Prague, Kamycka 129, Prague 165 21, Czech Republic; * Corresponding author: hyseks@fld.czu.cz INTRODUCTION Raw wood is the main component used in the production of composite materials. With increasing demands in the woodworking industry, the importance of alternative sources for the production of wood-based materials is increasing and becoming more topical (Dziurka et al. 2015). Various materials based on cellulose and lignin are currently used for the production of agglomerated materials (Ye et al. 2007). Agricultural products that are used to produce composite materials include rice stalk, coconut fiber (de Melo et al. 2010; Zhang and Hu 2014), corn stalk (Akinyemi et al. 2016), jute (Goswami et al. 2008), bagasse (Silva et al. 2016), bamboo (Widyorini et al. 2016), wheat straw (Zhang et al. 2011), and rapeseed (Dziurka et al. 2005). This study primarily focused on the production of composite materials made from rapeseed. Using post-harvest rapeseed residues, which have not yet been industrially used as the main component in composite materials, has the potential to contribute to solving the shortage of wood in the woodworking industry in the European Union.