Revisiting hardboard properties from the fiber sorting point of view

This study investigates the effects of fiber dimensions on hardboard properties. Fiber size is determined by the amount of energy applied during refining, and fiber size affects board properties; that is, production cost and board performance are closely related. Therefore, in the present paper, the effects of fiber dimensions on hardboard performance have been investigated. To optimize the hardboard process, fiber size was varied via screening, and the screen fractions were further classified using a Bauer-McNett apparatus. Hardboards were produced with mixtures of classified fibers. Bending strength, internal bond, and thickness swelling of the final boards were evaluated according to EN 310, EN 319, and EN 317, respectively. The effects of fiber size on the investigated properties were analyzed by means of multivariate linear regression. Generally, a higher proportion of small fibers appears to improve board performance presumably due to the higher specific surface area of fibers, which facilitate interfiber bonding.