caa a22 4500 378903225 CHVBK 20180305123523.0 cr unu---uuuuu 161128e20041201xx s 000 0 eng 10.1515/epoly.2004.4.1.398 doi (NATIONALLICENCE)gruyter-10.1515/epoly.2004.4.1.398 Rheological behaviour of urea-formaldehyde adhesive resins [Elektronische Daten] [Peep Christjanson, Aime Suurpere, Kadri Siimer] 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. © 2013 by Walter de Gruyter GmbH & Co. Christjanson Peep Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Fax 372 620 2903 aut Suurpere Aime Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Fax 372 620 2903 aut Siimer Kadri Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Fax 372 620 2903 aut e-Polymers De Gruyter 4/1(2004-12-01), 398-407 2197-4586 4:1<398 2004 4 epoly https://doi.org/10.1515/epoly.2004.4.1.398 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1515/epoly.2004.4.1.398 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Christjanson Peep Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Fax 372 620 2903 aut NATIONALLICENCE 700 1- Suurpere Aime Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Fax 372 620 2903 aut NATIONALLICENCE 700 1- Siimer Kadri Department of Polymer Materials, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Fax 372 620 2903 aut NATIONALLICENCE 773 0- e-Polymers De Gruyter 4/1(2004-12-01), 398-407 2197-4586 4:1<398 2004 4 epoly CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter