This work examines the performance of three formaldehyde scavengers
in wood-based panels. Sodium metabisulfite, ammonium bisulfite and urea were
applied in different physical forms during particleboard production, and the
resulting physico-mechanical properties (internal bond strength, thickness swelling,
density and moisture content) and formaldehyde emission levels were compared.
Formaldehyde content was measured using the perforator method, and formaldehyde
emission was evaluated both by desiccator and gas analysis methods. The
chemical reactions involved in each formaldehyde scavenging process are proposed
and discussed. The tested scavengers showed distinct performances under the different
emission testing conditions, which were interpreted in terms of the stability of
the chemical compounds formed upon formaldehyde capture. Sodium metabisulfite
proved to be an excellent scavenger for all formaldehyde methods allowing the
production of particleboard panels with zero formaldehyde emission.