Oriented structural straw board

Abstract: Wheat straws were split longitudinally using a specially designed straw splitter. Oriented structural boards made from the split straw strands were fabricated with polymeric diphenylmethane diisocyanate (pMDI) resin. The effects of the split straw strand length, resin content, and panel density on the properties of oriented structural straw board (OSSB) were investigated. Dimensional analysis showed that the average length of split straw strands after screening of the fines was 83.74 mm. More than 70% of the straw strands were in the range of 50 to 90 mm in length. The bending properties of the OSSB were highly related to the length of the split straws. The modulus of rupture (MOR) and modulus of elasticity (MOE) increased significantly as the split straw length was increased, particularly from 11 mm to 45 mm. The preferable length of the split straw was at least 40 mm to satisfy the MOE requirements. For a given pMDI content level, the internal bond (IB) strength increased linearly with an increase in panel density, which is consistent with previous results for wood-based panels. This study demonstrated that satisfactory OSSB can be made using approximately 3% pMDI at an average panel density of 640 kg/m³ to comply with the North American OSB products standard.

Abstract: Oriented Structural Straw Board (OSSB) panels are composites made from straw originally from agricultural residues and non-formaldehyde based adhesive, whose main application is for construction as a closing and ceiling material. The objective of this study was to evaluate the effect of the polyurethane adhesive content on physical and mechanical properties of OSSB produced with locally available SbS (soybean straw). Four castor oil based polyurethane ratios (6%, 9%, 12% and 15%, by mass of the SbS) were tested. OSSB was evaluated according to European standards for wood-based composites; also, a physical and chemical characterization of the SbS was performed. SbS has an irregular shape, which reduced the OSSB mechanical performance due to the low densification of the composite and the development of transversal cracks on the SbS after the OSSB manufacturing process. The static bending and thickness swelling performance of SbS OSSB was not improved by the increase of polyurethane adhesive content. SbS low ash content and neutral pH extractives indicates that probably its chemical properties should not affect the setting of the adhesive.

Abstract: PROBLEM TO BE SOLVED: To provide a method for surface treating a decorated OSSB board bound in a plate-like shape, by bonding an end face material to the end face of a side end face of a thick OSSB board, and applying surface treatment to the whole of the OSSB board including the end face by an NC machine as it is.SOLUTION: The method for processing the OSSB board comprises the steps of: bonding the end face material which comprises natural wood or a solid wood material and has the same size as the total length of the end face, to the end face which serves as a side end face, a vertical end face or an end face of an opening of the thick OSSB (oriented structural straw board) board, which is obtained by using the wheat straws after harvesting as a main raw material and binding the wheat straws into the plate-like shape by using MDI (methylene diphenyl diisocyanate); and applying surface treatment to the OSSB board by the NC machine, with the end face material bonded to the end face.

Abstract: Considerable straw-based composite research has been done due to the shortage of wood resources and environmental impact from burning straw.To date,various efforts have involved making straw panels with a mixed degree of success.The Forest Products business unit of Alberta Research Council has developed oriented structural straw board(OSSB) in cooperation with Panel Board Holding BV of The Netherlands(PBH).PBH has built up the world's first OSSB factory in China – Yangling board manufacturing of the Leenderson Panel Company.The OSSB product is comparable to wood-based oriented strand board(OSB) in both physical and mechanical properties at comparable densities.For their OSSB application,PBH has also developed a light steel-framed OSSB housing system.This paper will outline the OSSB's manufacturing technique,panel properties,and its housing system.