sol-gel transition; resorcinol-formaldehyde gel; rheology; viscoelasticity; gelation time
Abstract :
[en] The sol-gel transition of organic gels prepared by polycondensation of resorcinol (R) with formaldehyde (F) in presence of sodium carbonate (C) was monitored by small amplitude oscillatory measurements, at a single frequency. The gelation time (t(g)) was determined from the evolution of the storage (G) and loss (G") moduli versus time. The influence of two synthesis variables, the resorcinol/sodium carbonate ratio (R/C) and the synthesis temperature (7), was investigated. The gelation time was found to decrease with increasing synthesis temperature and decreasing R/C ratio. The apparent activation energy of the reactional system leading to the gelation, calculated from the gelation times obtained between 50 and 90 degrees C, was found to be close to 80 kJ mol(-1) and independent of the R/C ratio. (c) 2006 Elsevier B.V. All rights reserved.
Disciplines :
Chemistry Chemical engineering
Author, co-author :
Job, Nathalie ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Génie catalytique
Panariello, Fabian
Crine, Michel ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires
Pirard, Jean-Paul ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Génie catalytique
Léonard, Angélique ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Opérations physiques unitaires - Département de chimie appliquée
Language :
English
Title :
Rheological determination of the sol-gel transition during the aqueous synthesis of resorcinol-formaldehyde resins
Alternative titles :
[fr] Détermination de la transition sol-gel lors de la synthèse de résines résorcinol-formaldéhyde en milieu aqueux
Publication date :
01 February 2007
Journal title :
Colloids and Surfaces A: Physicochemical and Engineering Aspects
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