the aim of this study was to explore the minimum amount of urea formaldehyde (uf) resin content and optimum particleboard density while maintaining boards’ quality to reduce production costs. board density at three levels (520, 620 and 720 kg m-3) and resin content (6, 7 and 8%) were variable parameters. stepwise multivariate linear regression models were used to evaluate the influence of board...

the acrylated epoxidized soy oil (aeso) was synthesized from epoxidized soy oil and its properties were investigated.  wheat straw particle boards were produced by the synthesized resin with 8% and 13% contents based on straws weight at three pressing times: 8,10 and 12 min. boards’ modulus of rapture, modulus of elasticity, internal bonding, minimum degree of thickness change and water absorpt...

The previous study on low mole ratio urea-formaldehyde (UF) and ureamelamine–formaldehyde (UMF) resins synthesized in the typical way as particleboard binders was repeated with the inclusion of a strong acidic reaction step at a mole ratio of 2.7 in the beginning of the resin synthesis procedure. The resulting UF and UMF resins showed longer storageand pot-lives, longer gel times, and the parti...

Urea formaldehyde resins were formulated with vatiables of three reaction pHs (1.0, 4.8, and 8.0 5.0) and three catalysts (sodium hydroxide, sodium hydroxide/ammonium mix, and triethanolamine) . The resins were prepared by placing all formaldehyde and water in reaction kettle and pH was adjusted with sulfnric acid and sodium hydroxide, respectively. Urea was added in 1.5 equal parts at 1 minute...

An experiment was conducted to investigate the effects of the resin solid content, catalyst content, and pH value obtained by the addition of two kinds of catalysts on the gel time of a urea–formaldehyde (UF) resin. Upon the addition of ammonium chloride, the pH value of the resin mixture decreased to 7 but not significantly further because of the limited free formaldehyde in the system. The pH...

Urea-formaldehyde (UF) resin (F/U: 1.25), melamine-urea-formaldehyde (MUF) resin (F/(U+M): 1.05), and three kinds of wood species including poplar (Populus davidiana Dode), beech (Fagus engleriana Seem.), and eucalyptus (Eucalyptus robusta Smith) were used to produce plywood. The effects of sealing treatment and wood species on the formaldehyde emissions were studied. The anatomical characteris...

Three formaldehyde-based resins were prepared: urea-formaldehyde (UF) resin without melamine modifier (named UF0 resin) and melamineurea-formaldehyde (MUF) resins with melamine modifier added at two different synthesis stages (named MUF1 resin and MUF2 resin). The effects of the melamine addition stage on the performance and curing behavior of MUF resin were studied. Three-ply plywood bonded by...

in this research, the effect of nanoclay on physiochemical, thermal and structural properties of urea formaldehyde resin (uf) was investigated. the prepared gluf resin was mixed mechanically with the 0.5, 1 and 1.5% nanoclay for 5 min at room temperature. the physicochemical properties of the prepared resins were measured according to standard methods. also, the thermal and structural changes i...

Six potentially important wood adhesives for gluing southern pine and white oak flakeboards were evaluated for their perfonnances in steam-injection pressing and conventional platen pressing. Of the six resins tested, polyisocyanate resin perfonned well in both steam injection and conventional platen pressings. Phenol-fonnaldehyde (PF) and melamine urea-fonnaldehyde (MUF) resins perfonned poorl...

A powdery product was obtained by the reaction of methylolated melamine with alkyl resorcinols to form melamine-bridged alkyl resorcinols (MARs). The effects of the addition of this powder on the bonding strength and formaldehyde emission of urea–formaldehyde (UF) resins were investigated. Three types of UF resins with a formaldehyde/urea molar ratio of 1.3 synthesized by condensation at pH 1.0...