Dimensional stability of flakeboards as affected by board specific gravity and flake alignment

Abstract

The objective was to determine the relationship between the variables specific gravity (SG) and flake alignment and the dimensional stability properties of flakeboard. Boards manufactured without a density gradient were exposed to various levels of relative humidity and a vacuum-pressure soak (VPS) treatment. Changes in moisture content (MC), thickness swelling, and linear expansion were measured and used to develop regression equations. Under board saturation conditions resulting from VPS, dimensional movement could be defined as a function of SG without regard to MC. The relationship between SG and MC was essential in defining dimensional stability changes at exposure conditions resulting in MC's below fiber saturation because equilibrium MC and equilibrium dimensional stability are independently time-related to SG and they vary with flake type and exposure conditions. Derived regression equations were used to predict thickness swelling in three-layer boards with reasonable accuracy. Reliable prediction of linear expansion depends on the analysis of many board properties.

Citation

Geimer, Robert L. 1982. Dimensional stability of flakeboards as affected by board specific gravity and flake alignment. Forest products journal. Vol. 32, no. 8 (Aug. 1982): Pages 44-52