Estimating the hydrolytic durability of cured wood adhesives by measuring formaldehyde liberation and structural stability

Influence of acrylamide copolymerization of urea–formaldehyde resin adhesives to their chemical structure and performance

“…In general, lower F/U mole ratios cause less formaldehyde emissions from the panel with an expense of panel properties, particularly internal bond strength and thickness swelling after water immersion for 24 h. 9 It was known that UF resin had the least hydrolytic stability among amino resins. 10 As a way of understanding of the formaldehyde emissions of amino resins, many studies attempted to measure hydrolytic stability of amino resin adhesives (UF resin or MUF resin). 5,[10][11][12] These studies suggested that the hydrolysis of UF resin consisted of different reversible reactions to those of the UF resin synthesis.…”

“…10 As a way of understanding of the formaldehyde emissions of amino resins, many studies attempted to measure hydrolytic stability of amino resin adhesives (UF resin or MUF resin). 5,[10][11][12] These studies suggested that the hydrolysis of UF resin consisted of different reversible reactions to those of the UF resin synthesis. For example, infrared spectra study showed major reduction of the content of methylol groups (CH 2 OH) while it increased tertiary amide.…”

Effect of γ-irradiation on the hydrolytic stability and thermo-oxidative behavior of bio/inorganic modified urea–formaldehyde resins

“…The emitted formaldehyde causes from a free formaldehyde present in UF resins after synthesis and mostly from hydrolysis of UF resins under acidic and moisture conditions. Many studies have recognized the hydrolysis as a responsible factor in long-term formaldehyde emission of UF resin bonded wood panels [6][7][8][9][10]. Hence, the efforts were directed to the better understanding of resin hydrolytic degradation process and ways of minimization of the formaldehyde emission.…”

Micro-Morphological Features of Cured Urea-Formaldehyde Adhesives Detected by Transmission Electron Microscopy

“…Further, as a binder, UF resin adhesives penetrated not only in cell lumens but also into tracheid walls [5]; thus interaction between wood and UF adhesives occurs continuously. Many studies have investigated the hydrolysis of UF resin adhesives to understand the mechanism of formaldehyde release, not only from pure cured UF resin adhesives [2,[6][7][8][9][10][11][12] but also from UF resin adhesive-bonded wood panel products [13][14][15][16]. The tendency toward hydrolytic degradation of a cured UF resin adhesives depends on its chemical structure and the degree of crosslinking and could be accelerated by high temperatures and strong acidic conditions [15].…”