Influence of the initial formaldehyde to phenol molar ratio (F/P) on the formation of a phenolic resol resin catalyzed with amine

Influence of cure conditions on properties of resol/layered silicate nanocomposites

“…Carbonates (sodium carbonates) and oxides (calcium or magnesium oxides) are also employed [38, 39]. Tertiary amines, in particular triethylamine, are also used [16, 19–22, 41] being it the selected catalyst throughout this work. NaOH was also chosen to compare its influence on the final properties of the composites for being one of the most worldwide used catalysts in phenolic synthesis and as representative of the hydroxides.…”

“…The initial F/P molar ratio is one of the most important factors on the formation of phenolic resol resins [20, 38, 41]. In the past, many authors reported the influence of the initial formaldehyde to phenol molar ratio in the synthesis of resol resins catalyzed with alkaline catalysts, such as sodium hydroxide and barium hydroxide [38, 39, 43].…”

“…Phenolic resins are irreplaceable materials for a wide range of industrial applications such as adhesives, coatings, laminates, and composites [16–22]. Phenolic resins are synthesized by the reaction of phenol with aldehydes, especially formaldehyde, and are classified as resols and novolacs depending on phenol/aldehyde ratio.…”

Chemical Structure and Curing Characteristics of Phenol Formaldehyde Resins Catalyzed with Calcium Oxide

“…There have been many attempts to cure PF resins faster, including mixed with various resins [3] , adding accelerators and different catalysts such as ester [4,5] , copolymerized urea [6][7][8] , carbonate [9,10] and amides [11,12] .…”

“…This type of resin have been widely used as industrial impregnating resins and adhesives in various applications for more than 50 years [1,2] . One of the drawbacks of PF resin is its slow cure which requires longer hot-pressing time and higher hot-pressing temperature for the manufacture of composite products.There have been many attempts to cure PF resins faster, including mixed with various resins [3] , adding accelerators and different catalysts such as ester [4,5] , copolymerized urea [6][7][8] , carbonate [9,10] and amides [11,12] .Faster curing PF resins may also be prepared by metallic ion catalysis, which increases the proportion of the free higher reactive para positions available for the reaction during curing of the resin. It was investigated that the valence and ionic radius of hydrated cations of basic catalyst on the mechanisms and kinetics of phenol formaldehyde…”