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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 1: Nanoparticles and Composite Materials I

CPP 1.3: Vortrag

Montag, 11. März 2013, 10:15–10:30, H34

An unusual viscosity behaviour of the nanocomposites — •Marta Lungova, Wim Pyckhout-Hintzen, and Dieter Richter — Forschungszentrum Julich, Germany

Many polymers have been modified by adding the suitable nanoparticles resulting in a higher modulus and viscosity. However, some systems showed the opposite effect [1]. The reduced viscosity was also observed on the system of linear PEO with PEO-grafted silica nanoparticles where in a similar way, the size of the nanoparticles is in the range of the tube diameter of the bulk polymer. The viscosity reduction becomes more evident with increasing Mw but crosses-over to the opposite, reinforcement effect, for high Mw of the matrix. This is apparently a function of the ratio between the radius of the nanoparticle and the Rg of the bulk polymer.

The SANS experiment (ILL,France and FRM II, Germany) showed that the polymer shell of the nanoparticle tends to be more swollen in the matrix of low Mw whereas with increasing Mw of the bulk the shell collapses and particles separate from the matrix resembling rigid particles with the typical reinforcement effect. The dynamics of the bulk polymer measured by NSE (ORNL, USA) were slowed down in a system with higher viscosity.

This work is a part of the European project DYNACOP supported by Marie Curie Action.

[1] Mackay M. at al, Nat.Mater., 2003, 762-6.