This project was carried out in three parts. Part one was to collect strands from commercial OSB mills and quantify how the strand shape mixtures found in the different mill samples impact OSBpanel properties. Part two quantified the impact of strand shape distributionon OSB production processes and panel properties. Part three, which is described in the this report, was carried out to determine whether relationships could be established between strand manufacturing condistions and strand shape. The reasoning behind the work was that if relationshiups could be established, strand shape factor could become a tool for OSB manufacturers to usein controlling strand quality and troubleshooting strand manufacturing problems.
The bending properties of aspen waferboard can be improved by increasing the resin content and/or board density. These options, however have limited effect and are very costly. On the other hand, panels produced with longer, oriented stands have demonstrated significant improvements in bending strength and stiffness. The panel industry has recently used wafers or strands up to approximately 102mm (4in), however, the utilization of much longer material is practical. In addition to more efficient use of the wood resource, structural panels with improved properties can penetrate more demanding applications, particularly as future engineering materials, and overcome some problems experienced with traditional wood composites such as creep. The overall objective of the study was to demonstrate that by using long strands, coupled with appropriate strand alignment, strand thickness, and face-to-core layer ratio, a structural panel can be produced with superior strength and stiffness in the aligned direction while maintaining adequate properties in the cross direction. The specific objective for this year's work was to establish the improved performance using panels produced in structural sizes and under conditions that parallel those of the industry more closely. Manufacturers of oriented strandboard and waferboard can use the information to produce high performance OSB panel products with minimal effects on production parameters and costs.
Previous research at Forintek Canada Corp. showed that by optimizing aspen strand alignment, strand length, strand thickness, and face-to-core (f/c) layer composition, three layer oriented strandboard (OSB) panels can be produced with bending properties significantly exceeding those of CSP commercial plywood. Also, the creep behaviour under room conditions was comparable for the two panel types. The specific objective for this year's work was to extablish the improved performance using panels produced in structural sizes and under conditions that parallel those of the industry more closely.