Significance and Use

This test method provides a simple means of characterizing the thermomechanical behavior of plastic compositions using a very small amount of material. Since small test specimen geometries are used, it is essential that the specimens be representative of the material being tested. The data obtained can be used for quality control and/or research and development purposes. For some classes of materials, such as thermosets, it can also be used to establish optimum processing conditions.

Dynamic mechanical testing provides a sensitive means for determining thermomechanical characteristics by measuring the elastic and loss moduli as a function of frequency, temperature, or time. Plots of moduli and tan delta of a material versus these variables can be used to provide a graphic representation indicative of functional properties, effectiveness of cure (thermosetting-resin systems), and damping behavior under specified conditions.

This test method can be used to assess the following:

5.3.1 The modulus as a function of temperature or aging, or both,

5.3.2 The modulus as a function of frequency,

5.3.3 The effects of processing treatment, including orientation, induced stress, and degradation of physical and chemical structure,

5.3.4 Relative resin behavioral properties, including cure and damping,

5.3.5 The effects of substrate types and orientation (fabrication) on elastic modulus, and

5.3.6 The effects of formulation additives that might affect processability or performance.

Before proceeding with this test method, refer to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or combination thereof, covered in the relevant ASTM material specification shall take precedence over those mentioned in this test method. If there are no relevant ASTM material specifications, then the default conditions apply.

1. Scope

1.1 This test method outlines the use of dynamic mechanical instrumentation for determining and reporting the viscoelastic properties of thermoplastic and thermosetting resins and composite systems in the form of rectangular bars molded directly or cut from sheets, plates, or molded shapes. The elastic modulus data generated may be used to identify the thermomechanical properties of a plastics material or composition.

1.2 This test method is intended to provide a means for determining the viscoelastic properties of a wide variety of plastics using nonresonant, forced-vibration techniques as outlined in Practice D 4065. In particular, this method identifies the procedures used to measure properties using what is known as a dual-cantilever beam flexure arrangement. Plots of the elastic (storage) modulus, loss (viscous) modulus, and complex modulus, and tan delta as a function of frequency, time, or temperature are indicative of significant transitions in the thermomechanical performance of the polymeric material systems.

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

1.4 Apparent discrepancies may arise in results obtained under differing experimental conditions. These apparent differences from results observed in another study can usually be reconciled, without changing the observed data, by reporting in full (as described in this test method) the conditions under which the data were obtained.

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

1.6 The values stated in SI units are to be regarded as standard.

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 and health practices and determine the applicability of regulatory limitations prior to use.

There is no known ISO equivalent to this standard.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D618 Practice for Conditioning Plastics for Testing

D4065 Practice for Plastics: Dynamic Mechanical Properties: Determination and Report of Procedures

D4092 Terminology for Plastics: Dynamic Mechanical Properties

D5279 Test Method for Plastics: Dynamic Mechanical Properties: In Torsion

Keywords

dual cantilever; dynamic mechanical rheological properties; linear displacement; modulus (storage; viscous; loss modulus; and complex); tan delta; viscoelastic behavior;

ICS Code

ICS Number Code 83.140.01 (Rubber and plastic products in general)

DOI: 10.1520/D5418-07

ASTM International is a member of CrossRef.

ASTM D5418