Preparation and characterization of foamed urea formaldehyde (UF) adhesive for wood

Abstract

In this study, urea formaldehyde (UF) resin was foamed using egg white (EW), blood albumin (BA), blood protein (BP) and liquid soap (SP), and the effect of foaming on the adhesive strength (IB), gelling time, density and water absorption (WA) was investigated. Black pine samples were used for the IB analysis. Two 50 mm x 50 mm x 5 mm wood samples were bonded to each other using 1-gram foamed UF and the IB strength was determined. In order to determine the water intake amounts, foamed UF was poured into the mold and allowed to solidify for 7 days. The density and water uptake amounts of the solidified UF were determined by keeping them in water for 24 hours. According to the obtained results, the foaming agents increased the volume of UF 2-3 times after 10 minutes of mechanical mixing and increased the gelation times. EW and BA increased IB strength while SP and BP decreased. No significant change was detected in the densities of the samples. With the foaming process, UF covered more surface area. this increased the gluing efficiency of UF. However, although SP and BP increased the volume of the glue, they decreased the adhesion strength. It has been determined that the gluing efficiency can be increased by foaming the glues. In this way, formaldehyde emission can also be reduced.