Resorcinol-formaldehyde resin is a material used in endodontic therapy in many foreign countries. With immigration to the United States increasing, American dentists need to become familiar with resorcinol-formaldehyde therapy. It contains two potentially toxic components, formaldehyde (liquid) and resorcinol (powder). Zinc oxide or barium sulfate may be used for radiopacity. When 10% sodium hy...

Glycolaldehyde, produced from cracking of glucose, was tested as a substitute for formaldehyde in urea-based wood adhesives. Initially, different parameters (water content, aldehyde/urea-ratio, curing temperature, and time) were screened to identify the optimal conditions providing highest bond strength. Afterwards, system reformulated 2-component compared urea-formaldehyde system, which showed...

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...

The objective of this preliminary study was to partially replace phenol in the synthesis of phenol-formaldehyde resin with feather protein. Feather protein–based resins, which contained one part feather protein and two parts phenol, were formulated under the conditions of two feather protein hydrolysis methods (with and without presence of phenol during hydrolysis), two formaldehyde/phenol mola...

condensation reaction of urea, casein and formaldehyde in the presence of varying proportion of resorcinol under alkaline condition. All the prepared resins were characterized by free-formaldehyde content, free-phenol content, viscosity measurements and infrared spectroscopy (IR). The resin samples were cured isothermally at 120oC using two different curing agents, p-toluene sulphonic acid (PTS...

This paper describes the carbonization behavior of phenol-formaldehyde resin (PF) blended in the presence of simple organic substances of m-phthalic acid (PA), trimesic acid (TMA) and phloroglucinol (PG). The weight loss and heat flow were monitored in order to study their carbonization behavior by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), respectively. These ...

Abstract Chestnut bur is an agro-waste material generated in the chestnut production. It a tannin-rich lignocellulosic which might be promising raw for low-formaldehyde composite particleboard production when using urea–formaldehyde (UF) as bonding adhesive. In this study, characteristics of were analyzed to assess its application value panel. Five-type particleboards manufactured from mixture ...

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...

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