Thermal stability and pyrolysis kinetics of lignin‐phenol‐formaldehyde resins

Abstract

A thermal stability and kinetic study from non-isothermal experiments of a commercial and a ligninnovolac resin mixed with two amounts of curing agent has been done employing thermogravimetric analysis technique. Three kinetic models have been tested: a single heating rate method, such as Coats-Redfern, employing several mechanistic functions and contrasted with Van Krevelen-it is the first time that this method has been employed in polymer degradation. Finally, the Ozawa method allowed the obtaining of the activation energy by the multiple-heating-rate without knowing the mechanism.Results show that commercial mixtures of resins lose less weight than lignin-novolac resins. The calculated kinetic parameters showed that Coats-Redfern gives similar results to Van Krevelen, which means that these methods are adequate for novolac pyrolysis, and Ozawa shows activation energies in accordance with the last mentioned models.

Thermal degradation characteristics of phenol–formaldehyde resins derived from beetle infested pine barks

“…Lignin-phenol-formaldehyde (LPF) resol resins were found to have higher thermal stability under both nitrogen and air conditions than PF resins with different degradation characteristics [18]. Meanwhile, the LPF novolac resins were found to be less stable at lower temperatures than PF resins, but they were comparable to PF resins at higher temperatures [20]. The addition of cellulose fibers to PF resol resins reduced thermal resistance of the resulting resol resins [21].…”

“…The inclusion of other materials, such as lignin and cellulose fibers, in the PF resin synthesis has been shown to modify thermal stability and degradation kinetics of the resulting resins [18,20,21,24]. Lignin-phenol-formaldehyde (LPF) resol resins were found to have higher thermal stability under both nitrogen and air conditions than PF resins with different degradation characteristics [18].…”

Synthesis and Characterization of Composite Material Based on Modified Phenolic Resin

“…After this temperature range slow weight loss was observed around 400°C temperature furthermore the thermo grams of all composites reveals that about 50% of weight loss occurred in the temperature range of 500°C temperature. Thermo gravimetric studies indicates the good interpenetration of thermosetting epoxy resin composites and these composite have very good thermal stability which proves suitability for high performance applications [23].…”

Polyphenolic resin synthesis: optimizing plantain peel biomass as heavy metal adsorbent

“…Besides, it is important to take into account that the majority of these structures exhibited a weight loss above 150 °C since it was pointed out before; these structures are possibly degraded if they are heated above the melting point temperature [8] . The BRS showed a particular behavior since water loss started at the beginning of the analysis, but weight remained relatively constant above 200 °C [8] .…”

“…Besides, it is important to take into account that the majority of these structures exhibited a weight loss above 150 °C since it was pointed out before; these structures are possibly degraded if they are heated above the melting point temperature [8] . The BRS showed a particular behavior since water loss started at the beginning of the analysis, but weight remained relatively constant above 200 °C [8] . This may be due to the formation of a great quantity of water molecules during the condensation synthesis of the polymer and a high grade of polymerization and to the drying processes, which give the hard plastic a great thermal stability due to the formation of a great molecular network when having phenolic groups with reactive carbons towards substitution by formaldehyde [6] .…”