ASTM D3835

Standard Test Method for Determination of Properties of Polymeric Materials by Means of a Capillary Rheometer

Summary Description

The ASTM D3835 test standard specifies the characterization of rheological properties of polymeric materials at various common temperatures and shear rates. The test is performed by loading material pellets into the preheated barrel of a capillary rheometer at a given test temperature and extruding the melt at a constant volumetric flow rate. Common properties that reference ASTM D3835 include the melt density, melt flow stability, shear viscosity vs. shear rate (including options for Weissenberg-Rabinowitsch and Bagley corrections), Mooney slip velocity vs. shear stress, extensional viscosity (by Cogswell, PELDOM and Binding methods), and die swell ratio vs. shear rate.

Additional Test Standards of Relevance

  • ISO 11443

Characterization Measurements and Relevant Tests

DatapointLabs offers a number of tests that address different properties covered under the ASTM D3835 standard. These include the following characterization measurements [bracketed links refer to relevant tests in the DatapointLabs Test Catalog]:

Melt Density

Melt Flow Stability

Capillary Rheology

  • Shear viscosity vs. shear rate; includes Weissenberg-Rabinowitsch correction [R-011]

  • Bagley correction: shear viscosity vs. shear rate; includes Weissenberg-Rabinowitsch and Bagley corrections [R-012]

  • Mooney slip: apparent (uncorrected) shear viscosity vs. shear rate, Mooney slip velocity vs. shear stress [R-016]

Very High Shear Capillary Rheology

  • Shear viscosity vs. shear rate (small diameter die); includes Weissenberg-Rabinowitsch correction [R-013]

Extensional Viscosity

  • Cogswell method: Cogswell extensional viscosity, shear viscosity vs. shear rate); includes Weissenberg-Rabinowitsch correction [R-014]

  • PELDOM method: PELDOM extensional viscosity, shear viscosity vs. shear rate [R-042]

  • Binding method: Binding extensional viscosity, shear viscosity vs. shear rate [R-017]

Die Swell (Laser Micrometry)

  • Die swell: die swell ratio vs. shear rate, shear viscosity vs. shear rate [R-030]

Slit-Die Rheology

  • Slit-die configuration: shear viscosity vs. shear rate; no Weissenberg-Rabinowitsch correction required [R-035]

Test Procedure and Equipment Used

The specific test procedure will vary by test and the individual test webpages (linked to above and below) should be consulted for relevant descriptions. In general, a capillary rheometer is used to determine the appropriate rheological property or properties under measure. Material pellets are loaded into the barrel of a capillary rheometer preheated to the test temperature. After melting, the material is extruded at a constant volumetric flow rate. Typically, a range of flow rates is used, covering a shear rate range of 10/s-10,000/s. The pressure drop across the die is measured by means of a pressure transducer for each flow rate, and shear viscosity vs. shear rate data are calculated, along with relevant corrections. For extensional viscosity, a zero L/D orifice die is employed. For die swell, a laser micrometer is used to measure extrudate diameter.

Sample Conditioning and Non-Ambient Testing

No relevant sample conditioning, apart from pre-test drying, if required (included as part of the test procedure). Similarly, no relevant non-ambient testing conditions, as the testing is inherently non-ambient.

Test Specimen Specification and Description

Specimen specifications under ASTM D3835 are as follows:

  • Pellets or suitable alternative; see Pellets for further details

Characterization Measurement Descriptions

Typical characterization measurements under ASTM D3835 include:

  • Melt Density: The density of the material in the melt state at a given temperature

  • Melt Flow Stability: The change in viscosity of the molten material as a function of time when extruded at a constant volumetric flow rate; a measure of material degradation

  • Shear Viscosity vs. Shear Rate: The resistance of the molten material to shear flow as a function of shear rate of the molten material

  • Weissenberg-Rabinowitsch Correction: A correction to the shear rate to accommodate the non-parabolic velocity profile of the melt flow in the capillary

  • Bagley Correction: A correction to the wall shear stress to accommodate the effects of the entrance and exit regions adjacent to the capillary

  • Mooney Slip Velocity vs. Shear Stress: The wall slip velocity as a function of the shear stress; particularly relevant for highly-concentrated emulsions or suspensions

  • Extensional Viscosity (Various Methods): In distinction to shear viscosity, the resistance of the molten material to extensional flow

  • Die Swell Ratio vs. Shear Rate: The increase in diameter of the extrudate relative to the diameter of the die, due to the release of contractive stress in the molten material following its passage through the capillary die

Complete Listing of DatapointLabs Tests Referencing ASTM D3835

The entire list of tests in the DatapointLabs test catalog that reference ASTM D3835 are as follows:

Standard Description
D-015 Melt Density
R-011 Capillary Rheology (1 Temperature)
R-012 Capillary Rheology with Bagley Correction (1 Temperature)
R-013 Very High Shear Capillary Rheology (1 Temperature)
R-014 Cogswell Extensional Viscosity
R-015 Thermal Flow Stability
R-016 Mooney Slip
R-017 Binding Extensional Viscosity
R-030 Die Swell Measurements by Laser Micrometry
R-032 Static Die Swell/Sag by Laser Micrometry
R-035 Slit-Die Rheology (1 Temperature, 1 Die)
R-042 PELDOM Elongational Viscosity
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