Advanced Testing of Rheology of Polymeric Melts

Rheology is the science of material’s flow and deformation under shear. All materials can flow under a sufficient time.The rheology road includes those materials exhibiting behavior varying from viscous liquid to elastic solid. By means of material’s rheological properties, we optimize processing conditions in extrusion, blow molding and injection molding. This helps in reducing final product cost while minimizing potential costs and thus increasing productivity.

At IIT Delhi, materials are tested for their rheological properties in Bohlin capillary rheometer, Malvern parallel plate rheometer and advanced Anton Paar MCR 702, Twin drive rheometer from Anton Paar. The above equipments offer one to conduct experiments on wide range of polymeric melts, suspensions, gels and solutions.

Suspensions, gels and solutions as well as high performance polymeric materials (blends, composites and nanocomposites) are tested in advanced twin drive rheometer. Apart from steady state, amplitude and frequency sweeps, MCR 702 is capable of measuring oscillatory sweeps at large amplitudes (LAOS), responses to dielectric field, optical rheograms, torsional and extensional rheology.

Anton Paar MCR 702, corresponding rheological plot and geometry of plates.
Currently, the research group is working on shear thickening fluids, a type of non-Newtonian liquid, to be used in protective systems in defence application. Microstructural rearrangements are a complex function of physical properties of suspended particles as well as suspending medium. Besides, a chemical/physical treatment to either systems or incorporation of additives into the suspension, correspondingly controls the rheological behaviour. The work emphasizes in understanding the fundamental concepts of deviations in the flow behaviour in both colloidal and non-colloidal suspensions. It was possible by means of rheology to link different suspension’s viscoelastic response to the forces occurring within the system.


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