Differential scanning calorimetry of phenol-formaldehyde resols. J.
Resoles are generally synthesized in multilevel processes using fossil components, such as phenol and formaldehyde (Knop and Pilato 1985, Pilato 2010).
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.
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.
In one of his most relevant experiments, blends containing 100 parts rubber and 40 parts of various phenolic resol resins were heated between the platens of a curing press for two hours at 155[degrees]C.
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
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.
Softwood bark pyrolysis oil-PF resols
for bonding OSB panels.
IR spectroscopy as a quantitative and predictive analysis method of phenol-formaldehyde resol
resins, which dominate synthetic PF technology, are not a feasible alternative for tannins.