The Effect of Foamed Urea-Formaldehyde Adhesive on Physical and Mechanical Properties of Medium Density Fiberboards (MDF)

Abstract

In this study, the effect of using foamed urea-formaldehyde (UF) adhesive in the production of medium-density fiberboard (MDF) on the properties of the board was investigated. A commercial foaming agent was used to increase the volume of UF adhesive by approximately 2.5 times. MDFs were produced using 6, 9 and 12 % adhesive and 1 % ammonium chloride hardener relative to the dry weight of the adhesive. The thermal degradation behavior of the foamed and control adhesives was determined by thermal analysis i.e., thermogravimetric (TGA) and derivative thermogravimetric (DTG) analyses. It was found that the foaming agent did not affect the thermal degradation of the adhesive. Scanning electron microscope images showed that the volume of foamed adhesive and blending efficiency increased. It was determined that MDFs produced with foamed adhesive had better water absorption and thickness swelling properties than control boards. However, the internal bond strength (IB) and modulus of elasticity (MOE) were found to be 8-14 % and 3-16 % higher, respectively, compared to the control samples. As a result, it can be concluded that the foaming process had a positive effect on the board properties and had the potential to reduce the amount of adhesive used.