Influence of disintegration technologies on particle structure and its mechanical properties

Abstract

ABSTRACT Wood is a highly optimised lightweight material showing excellent mechanical properties in the fibre direction. However, strength and stiffness are low perpendicular to grain. Due to knots, stem taper and spiral grain, the wood material includes local and global fibre deviations. Mechanical disintegration of logs into veneers and sawn timber is more or less ignoring the orientation of the natural wood structure, reducing mechanical properties of the grown tree. This is also true for particle production processes e.g. for OSB or particleboard, which also applies cutting and crushing technologies. As a result, conventional mechanical disintegration of logs means, the destruction of a highly optimised structure, which is always accompanied by a significant reduction of mechanical properties. The basic idea of the novel non-cutting chipless particle production process is to preserve the natural structure by employing squeezing and shear forces. These squeezing and shear forces lead to the mechanical disintegration of the logs primarily in the fibre direction, whereby long fibrous particles, so-called macro-fibres, are gained. Macro-fibres gained from this process prove excellent strength properties.