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Phenol–formaldehyde‐type resins made from phenol‐liquefied wood for the bonding of particleboard

“…1 Furthermore, it has been accepted that wood composite boards bonded with PF resins emit almost no formaldehyde gas. 2,3 Urea-formaldehyde (UF) resins are currently used for bonding interior-grade wood composite boards, such as particleboard, medium-density fiberboard, and hardwood plywood. UF resins are low cost and give adequate strength properties, but the boards have a formaldehyde emission problem, which has been proven to be difficult to resolve completely.…”

Online monitoring of synthesis and curing of phenol–formaldehyde resol resins by Raman spectroscopy

“…The methylolation stage of the synthesis is followed by the condensation stage, in which the methylol groups react with the free sites of other phenolic species yielding methylene bridge structures between the phenolic rings [1,2]. The formation of dibenzyl ether bridges resulting from the reactions of two methylol groups is not favored in highly alkaline conditions [3][4][5]. The resol resin synthesis is halted when the appropriate degree of condensation in the resin (viscosity) has been achieved.…”

Kinetics studies and characterization of poly(furfuryl alcohol) for use as bio‐based furan novolacs

“…This class of resins has been used in a growing number of applications over the years as their wide‐ranging value has been discovered . Novolac phenolics are synthesized using stoichiometric ratios of phenol and formaldehyde using an acid catalyst and give rise to higher molecular weight crosslinked resins that can be thermally cured into high‐temperature polymers and composites, which can be used in structural applications where heat‐resistant materials are needed . Using large excesses of phenol to formaldehyde or acetone will halt the reaction at formation of dimers and low molecular oligomers.…”

“…Using large excesses of phenol to formaldehyde or acetone will halt the reaction at formation of dimers and low molecular oligomers. The most common of these derivatives is the bisphenol family of molecules, such as bisphenol‐A (BPA) and bisphenol‐F (BPF), where bisphenols can be isolated for use in various other resins and polymer systems (e.g., epoxy resins, vinyl ester resins, polyurethanes, and polycarbonates) . Thermoplastic novolac oligomers formed from the reaction of phenol with formaldehyde are the basis for a number of applications; they can be cured with latent formaldehyde to form temperature‐ and chemical‐resistant thermosetting materials that are used in infrastructure applications such as plywood adhesives and insulation, or aerospace applications such as jet turbine exhaust nozzles…”

“…Despite the ability to renewably produce phenol and its derivatives, formaldehyde, and acetone, poly(furfuryl alcohol) (PFA) alternatives are an attractive alternative . The major advantage of PFA‐based resins over phenolics is that furfuryl alcohol (FA) and its derivatives already contain the hydroxyl methyl group that is found on the reactive intermediate during phenolic formation . This hydroxyl methyl group enables facile acid‐catalyzed polymerization of FA to PFA (Figure ).…”