Foamed Thermoset Resins for Enhanced Mechanical Properties and Reduced Formaldehyde Emissions in Particleboard

Abstract

Urea formaldehyde (UF) and phenol formaldehyde (PF), the most commonly used thermosetting adhesives in the particleboard (PB) industry, release formaldehyde, which is harmful to both humans and the environment. This study aimed to reduce glue consumption in PB with lower formaldehyde content by foaming the glue. The UF and PF were foamed using gelatin (GL), an animal protein, and the results were compared with those performed using sodium bicarbonate (SB) foaming agent and neat (UF and PF as controls) glue.  SB and GL foaming agents increased the volume of the UF and PF resins by 1.5 and 2 times, respectively. PB characterization was carried out mechanically, physically, and morphologically. A perforator analysis was performed to determine the formaldehyde content in PB. Results showed that the foaming process generally improved the mechanical properties except for 10% SB and 10% GL. Analysis showed that foaming reduced the PB moisture content and improved water absorption and thickness swelling, except for 10% SB and 10% GL. SEM analysis indicated a successful foaming process. GL and SB reduced the formaldehyde content of the PBs. In conclusion, PB can be produced using 10 to 20% less adhesive through the foaming method by GL.