Effects of moisture content of wood-based panels on formaldehyde releases

The influence of moisture content (MC) on formaldehyde emission from wood-based panel was analyzed by using desiccator and perforator methods.The results show that the effects of MC on desiccator values for different kinds of panels are obviously different,but the influence of MC by the desiccator method is not obvious.For particleboard and MDF:if MC is within 4%-9%,formaldehyde emission gradually increases logarithmically with MC increasing;if MC within 9%-13%,formaldehyde emission almost keeps constantly; if MC within 13%-15%,formaldehyde emission decreases swiftly with MC increasing.On the other hand,for decorative MDF (DMDF),a conic relationship exists between formaldehyde emission and MC.For block board and plywood,when moisture content is within 6%-14%,formaldehyde emission increases linearly with MC increasing.If formaldehyde is measured by desiccator method,for particleboard and MDF,MC should be controlled within 9%-13%,while MC of DMDF should be within 7%-9%.On the other hand,the effects of MC on perforator values are obvious.When MC is within 3%-16%,perforator value increases linearly with MC increasing.It is effective to apply the MC correction factor to the perforator value when MC is within 3%-13%.