Shearing equipment tests, instrumentation

Extensional Viscosity. All three types of extensional viscosity can be measured (101,103) uniaxial, biaxial, and pure shear. Only a few commercial instruments are available, however, and most measurements are made with improvised equipment. Extensional viscosity of polymer melts can be estimated from converging flow (entrance pressure) or from a melt strength drawdown test (208). 

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