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SUMMARY:In addition to pyrolysis and degradation with superheated steam the hydrogenolytic degradation of cured phenolic resins induced by hydrogen-donors has been investigated. Especially with 1,2,3,4-tetrahydronaphthaIene (tetralin) a considerable amount of transferred hydrogen to the dispersed resin particles, involved with formation of naphthalene, has been observed at 400°C. With total maximal yields of 98 wt.-% (ref. to the initial amount of phenolic resin) of phenol, methyl phenols, and oligomerous phenolic degradation products a recovering of industrial phenolic resin wastes should be possible. Kinetic and scanning electron microscopic investigations are employed to give some mechanistic explanations involving the hydrogenolytic liquefaction of cured phenolic resins.

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ZUSAMMENFASSUNG:Der zeitliche Verlauf der Polykondensation von Phenol mit Formaldehyd zu Resolen wird anhand eines kinetischen Modells mit einem Mikrocomputer simuliert. Durch Variation der Geschwindigkeitskonstanten und des Ausgangsmolverhaltnisses von Phenol und Formaldehyd wird der Einflun unterschiedlicher Reaktionsbedingungen auf wichtige Harzeigenschaften wie Restmonomergehalt, zahlenmittlerer Polymerisationsgrad, Verzweigungs-und Methylolierungsgrad untersucht. Die Eigenschaftsmerkmale der Endprodukte werden insbesondere durch das AusmaB intramolekularer Vernetzungen, d. h., durch den Mikrogelanteil beeinflufit. SUMMARY:The poiycondensation of phenol with formaldehyde to resole type phenolic resins has been studied using a kinetic model suitable for computer simulation. Important properties like residual amounts of monomers, number average degree of polymerization as well as degrees of branching and methylolation are calculated as functions of time for different values of initial molar ratios of phenol to formaldehyde and various rate constants. In addition the influence of intramolecular curing, due to formation of loops has been discussed in detail.