Using an ARES Rheometer to investigate the β-relaxation change of graphene poly(ethyl methacrylate) nanocomposite

Here we describe the application of an ARES Rheometer (TA Instruments) with a rectangular torsion fixture, to investigate the β-relaxation change of poly (ethyl methacrylate)/ graphene oxide. It is observed that graphene increases both the glass transition and the β-relaxation temperature, but the β-relaxation to a lesser extent.

Preventing Wall Slip in Rheology Experiments

Wall slip is a common problem when testing highly concentrated emulsions or suspensions on a rheometer. It is usually caused by large velocity gradients in a thin region adjacent to the wall. When slip occurs, the measured viscosity can be significantly lower than the actual viscosity of the sample. To overcome this influence, we have introduced a series of roughened surface geometries, such as crosshatched or serrated plates, which significantly improve the contact between the geometry and the sample to reduce slip.