Resols

Resols

 

(also A-stage resins), the thermosetting products of the polycondensation of phenols with aldehydes, mainly formaldehyde, of low molecular weight (400–1,000). Resols are viscous liquids or solid products that vary in color from light yellow to black. Reactive methylol (—CH2OH) groups are contained in the macromolecules of resols.

References in periodicals archive ?
Differential scanning calorimetry of phenol-formaldehyde resols.
IR spectroscopy as a quantitative and predictive analysis method of phenol-formaldehyde resol resins.
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.
TABLE 1 Characteristics of neat resols and resol-clay composites.
The resins with adequate vulcanizing properties produced easily removable flexible samples, whereas non-reactive resols acted more as plasticizers, leading to a mass of partially sticky decomposed rubber and chunks of hard resin.
As a result of dynamic mechanical analysis (DMA) carried out on resols at 110-125[degrees]C with a rapid heating schedule to simulate the pressing conditions used in the manufacture of oriented strand board and plywood, it was found that this analytical method is useful for measuring the cure time, vitrification time as well as other relevant parameters of phenolic resins as affected by the temperature and resin composition (ref.
The broadening of the resonances in the solid-state NMR spectra due to loss of molecular mobility enables only to ascertain that methylene formation (25-50 ppm) is the curing reaction of resols [16].
The formation of dimers with p,p'-methylene in condensation between HM phenols is the reaction occurring at the highest rate in the synthesis of resol resins.
Resols are obtained as a result of alkaline catalysis and an excess of formaldehyde.
These first stoichiometrically derived phenolics were called resols or one-steps, because cure occurs in a single step.
Thus resol resins, which dominate synthetic PF technology, are not a feasible alternative for tannins.