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Mooney Slip

Test ID  

In highly filled materials, slip can occur in capillary flow beyond a critical stress level. This test attempts to quantify the critical stress level. The sample, dried if needed, is loaded into a preheated test barrel of a capillary rheometer. A range of flow rates is used, attempting to cover a shear rate range of 10-10,000/s. Capillary viscosity measurements are performed using two dies, 0.5 and 1 mm diameter, but with the same 20 L/D. In the absence of slip, the data from these two measurements coincide.    
When slip is measurable, the results are presented in terms of a slip velocity versus shear stress curve. This data appears in Matereality as Capillary Viscosity  
Replicates (# of times this test is repeated)  
0.5 - kg of pellets [details]


Slip is most commonly seen with highly filled materials such as MIM and CIM feedstocks. It can also be observed in fiber filled polymers. Slip is implicated in the development of flow instabilities such as shark skin and slip stick flows.