Determination of the rheological properties of aqueous solutions of branched PEO-PPO-PEO copolymers. Confrontation with small-angle neutron scattering studies

• Published in: Macromolecular symposia. Vol. 166; no. 1; pp. 127 - 138
• Main Authors: Perreur, Christelle, Habas, Jean-Pierre, Peyrelasse, Jean, Lapp, Alain, Francois, Jeanne
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag GmbH 01-03-2001; WILEY‐VCH Verlag GmbH
• Subjects: Aqueous solutions; Copolymers; Mathematical models; Micelles; Neutron scattering; Rheological properties; Styrene acrylonitrile resins; Viscosity
• ISSN: 1022-1360; 1521-3900
• DOI: 10.1002/1521-3900(200103)166:1<127::AID-MASY127>3.0.CO;2-Z

The physico‐chemical properties of Tetronic® 908 in aqueous solution have been explored on a wide range of temperature and concentration. This system presents interesting rheological properties depending on the polymer concentration in solution, and temperature. For weight percentage p comprised between 5% and 20%, the viscosity of the solution passes through a maximum. Small angle neutron scattering experiments show that the increase in the viscosity is due to the progressive aggregation of the chains. For higher weight percentages, the viscosity of the system diverges and the mixture becomes “gel‐like”. SANS studies of the same solution indicate that the micelles are organized in a cubic structure. We have developed a model which suitably describes the SANS curves of the system in the region where micelles are formed. It allows the calculation of several parameters (volume fraction of the micelles, size, composition). The evolution of these parameters with temperature and polymer concentration is detailed. Comparisons with models of literature are discussed.