International. The shift to water-based coatings makes coatings more sensitive to this mineral. As a consequence, the durability of wood and coatings can be adversely affected.
The objective of a study was to elucidate the influence of wood substrates on the water permeability of the applied coating.
Pine wood, oak and teak were selected as the types of wood, covering a whole range of wood from low to high density.
Three types of coatings were formulated: a solvent-based alkyd, a water-based alkyd, and a water-based acrylic. For all combinations of wood cladding, water transport appeared to be limited externally (i.e. coated). The loss of bound water began only after the evacuation of free water, which showed a local thermodynamic equilibrium associated with bound and free water.
The researchers further compared the water permeability of free films and wood-supported films to understand the influence of wood cladding interactions. They found that the interaction of the coating with the wood does not influence the permeability of the water for the combinations considered. In addition, permeability is largely determined by solubility in water.
Source: www.sciencedirect.com
