ORIENTING LIGNOCELLULOSIC FIBERS AND PARTICLES BY MEANS OF A MAGNETIC-FIELD

Fiber and particle alignment in composite materials may be used to tai lor material and object properties to specific performance requirement s. The present research demonstrates that alignment of ferromagnetical ly modified slender wood particles in magnetic fields is feasible. Mag netic torque, which causes rotation, increases linearly with the amoun t of magnetic material on particle surfaces. Below magnetic saturation , magnetic torque increases with increasing strength of the applied fi eld; closer to magnetic saturation, torque becomes less dependent on t he applied field strength. Magnetic torque maxima occur at field-to-pa rticle axis angles above 45 degrees. Polarity switches of the applied magnetic field increase particle rotation rates and may counter perman ent magnetization, which otherwise tends to impede full particle align ment.