Über die Härtungsreaktion von Phenol‐Formaldehyd‐Harzen I

Borosgyevi, Von E.; Tüdős, F.; Szundi, István

doi:10.1002/apmc.1971.050150101

Cited by 6 publications

(2 citation statements)

References 27 publications

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“…Thus, the chemical bonding unites the separated microparticles of the suspension to form an overall network. The structure build-up occurs otherwise in the cure of phenol-formaldehyde resins [16]. In the latter case, the formation of a covalent network proceeds mostly by addition of short chemical crosslinks (methylene groups) between aromatic rings, and the role of associative interactions and water-containing clusters is essentially smaller.…”

Section: Resultsmentioning

confidence: 99%

“…The gel time was determined by extrapolating the reciprocal of zero shear viscosity and by values of storage and loss moduli. The curing process of phenol-formaldehyde resin was described also by a power law increase in viscosity [16]. Rheological measurements by means of rotational viscometers are quite popular in studies of curing processes of UF resins, cf., e.g., ref.…”

Section: Introductionmentioning

confidence: 99%

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Rheological behaviour of urea-formaldehyde adhesive resins

2004

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An attempt is made to describe the complicated rheokinetic behaviour of urea-formaldehyde resins during storage, in close connection with the changes in their chemical structure. The alkali-promoted non-linear polycondensation during resin storage is evaluated by pre-gel viscosity measurements. Viscosity changes are described by a power law function using extrapolation to zero shear and infinitely high shear rates. During most of the period of viscosity increase, the rheological behaviour of studied resins is similar. The deviation from the power law dependence occurring in the initial low-rate growth of viscosity takes place because of formaldehyde redistribution, which does not lead to covalent network build-up. In the presence of methanol this period is extended due to the formation of stable methoxymethylene groups.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rheological behaviour of urea-formaldehyde adhesive resins

2004

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The curing of phenol‐formaldehyde resins III

Gyevi

Tüdős

1974

Angew. Makromol. Chem.

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A kinetic investigation has been made of the curing process of phenol-formaldehyde resins by the method of adiabatic heat measurements. The applicability of rate equations related to adiabatic reactions for the given process has been examined. It was found that the curing of phenol-formaldehyde resins in closed system cannot be considered as an unidirectional reaction. In circumstances analogous to practical application the curing of resins takes place parallel to the evaporation of water. Adding a further term to the rate-equation of the strictly adiabatic reaction taking into account the evaporation, this process also can be described with an accuracy meeting the requirements of the practice. ZUSAMMENFASSUNG:Die Aushiirtung von Phenol-Formaldehyd-Harzen wurde durch adiabatische Messung der Reaktionswiirme untersucht. Dazu wurde die Verwendbarkeit von Geschwlndigkeitsgleichungen, die fur adiabatisch verlaufende Reaktionen abgeleitet wurden, gepriift. Die Phenolharzhartung kann in geschlossenen Systemen nicht als in nur eine Richtung verlaufende Reaktion angesehen werden. Unter den Bedingungen der Praxis verlauft die Hirtung parallel zur Verdampfung von Wasser. Deshalb muB in die genannte Geschwindigkeitsgleichung ein weiteres Glied aufgenommen werden, das die Verdampfung berucksichtigt ; dann kann der ProzeB mit hinreichender.Genauigkeit beschrieben werden.In the course of studying the curing of phenol-formaldehyde resins, in our previous experiments 1 . we tried to follow the process by viscosimetric, dilatometric and calorimetric methods. In our present paper we describe the method ofadiabatic reaction heat measurements. In a previous publication we derived equations expressing adiabatic reactions of different order, presented the function of an adiabatic calorimeter constructed by us, and described the application of the method in the case of polyurethane resins. The choice fell on polyurethane as the first model as the measurement of polyaddition

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Computer‐simulation der polykondensation von phenol mit formaldehyd

Steffan¹

1985

Angew. Makromol. Chem.

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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.

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Über die Härtungsreaktion von Phenol‐Formaldehyd‐Harzen I

Cited by 6 publications

References 27 publications

Rheological behaviour of urea-formaldehyde adhesive resins

Rheological behaviour of urea-formaldehyde adhesive resins

The curing of phenol‐formaldehyde resins III

Computer‐simulation der polykondensation von phenol mit formaldehyd

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