ASTM D4440-23 - Standard Test Method for Plastics: Dynamic Mechanical Properties Melt Rheology

1.1 This test method outlines the use of dynamic mechanical instrumentation in determining and reporting the rheological properties of thermoplastic resins and other types of molten polymers. The method is useful for determining the complex viscosity and other significant viscoelastic characteristics of such materials as a function of frequency, strain amplitude, temperature, and time. It is known that fillers and other additives influence rheological properties.

1.2 It incorporates a laboratory test method for determining the relevant rheological properties of a polymer melt subjected to various oscillatory deformations on an instrument of the type commonly referred to as a mechanical or dynamic spectrometer.

1.3 This test method is intended to provide a means of determining the rheological properties of molten polymers, such as thermoplastics and thermoplastic elastomers over a range of temperatures by nonresonant, forced-vibration techniques. Plots of modulus, viscosity, and tan delta as a function of dynamic oscillation (frequency), strain amplitude, temperature, and time are indicative of the viscoelastic properties of a molten polymer.

1.4 This test method is valid for a wide range of frequencies, typically from 0.01 Hz to 100 Hz.

1.5 This test method is intended for homogenous and heterogeneous molten polymeric systems and composite formulations containing chemical additives, including fillers, reinforcements, stabilizers, plasticizers, flame retardants, impact modifiers, processing aids, and other important chemical additives often incorporated into a polymeric system for specific functional properties, and which could affect the processability and functional performance. These polymeric material systems have molten viscosities typically less than 10⁶ Pa·s (10⁷ poise).

1.6 Test data obtained by this test method are relevant and appropriate for use in engineering design.

1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.