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Detection of Structure and Morphology by means of Rheological Methods

Rheological properties of polymers have important implications in processing and in many and diverse applications.

For many years, rheology has been used as semi-quantitative tools in polymer science and engineering.

The relationship between the structure and rheology of polymers is of practical interest for three reasons: Firstly, rheological properties are very sensitive to certain aspect of structure and they are simpler to use than other analytical methods, such as nuclear magnetic resonance. Secondly, it is the rheological properties that govern the flow behavior of polymers when they are processed in the molten state or as solution. Thirdly, defined mechanical properties are needed for the application of polymers in a lot of different fields.

Considering the structures and structure formation polymers in dependence from different parameters are the focus of joint simulations and various experiments.

Methods

Multiwave oscillation

Large Amplitude Oscillatory Shear Rheology using Partitioned Plate and Cone on Highly Viscous Fluids

Orthogonal Superposition or oscillating compression of soft polymeric solids

SER Universal Testing Platform  for Uniaxial Extension with defined Hencky strain in a rotational rheometer

Fields

  • Nucleated Crystallization of semicrystalline polymers in order to improve mechanical properties
  • Characterization of the Spinnability of Semicrystalline Polymers
  • Testing of Hydrogels for use in the field of biosensoric devices, diagnostic, actuators and microfluidic. Very important are mono- and bi-responsive hydrogels for the microsystem technique.

Examples

Fig. 1: The storage modulus of isotactic polypropylene during isothermal crystallization at 138 °C in dependence on different shear conditions. The samples PP/PCC contain 5 wt.-% acicular precipitated calcium carbonate as whisker particles.
Fig. 2: First heating scans of the samples in Fig.1 after isothermal crystallization

Selected Publications

R. Vogel, M. Vučak, C. Nover, L. Peitzsch Precipitated calcium carbonate as carrier particles of ‘dry liquids’ for post-processing crosslinking reactions Rubber Fibres Plastics International 8 (2013) 1, 36-39

R. Vogel, R. Boldt, M. Vučak, C. Nover , L. Häußler, H. Brünig:Acicular precipitated calcium carbonate as inorganic whisker for reinforcing of polypropylene fibers e-Polymers 13 (2013) 1, 300

R. Vogel, R. Boldt, M. Vučak, L. Häußler Shear-Induced Shish-Kebab Structures in Isotactic Polypropylene using Acicular Precipitated Calcium Carbonate as Whisker Polymer Engineering and Science 54 (2014) 9, 2057-2063