Form and mass changes of composite panels under variable environment humidity

The aim of this study was to determine the influence of relative humidity on the form and mass of composite panels produced from wood-based panels covered with aluminium plate on one side. Part of the samples was additionally covered with aluminium foil on the side opposite to aluminium plate. HDFs, MDFs and particleboards were used as base material. The results of experiments show that relative humidity changes cause geometrical deformations and mass changes of composite fibre-based panels. The largest permanent form changes (i.e. that remained after the cycle of air relative humidity changes was finished) were observed for material moderately reacting to humidity changes.