ASTM E1640-04

This test method can be used to locate the glass transition region and assign a glass transition temperature of amorphous and semi-crystalline materials.

Dynamic mechanical analyzers monitor changes in the viscoelastic properties of a material as a function of temperature and frequency, providing a means to quantify these changes. In ideal cases, the temperature of the onset of the decrease in storage modulus marks the glass transition.

A glass transition temperature ( T_g ) is useful in characterizing many important physical attributes of thermoplastic, thermosets (see SRM 18R-94), and semi-crystalline materials including their thermal history, processing conditions, physical stability, progress of chemical reactions, degree of cure, and both mechanical and electrical behavior. T _g may be determined by a variety of techniques and may vary in accordance with the technique.

This test method is useful for quality control, specification acceptance, and research.

1.1 This test method covers the assignment of a glass transition temperature (Tg) of materials using dynamic mechanical analyzers.

1.2 This test method is applicable to thermoplastic polymers, thermoset polymers, and partially crystalline materials which are thermally stable in the glass transition region.

1.3 The applicable range of temperatures for this test method is dependent upon the instrumentation used, but, in order to encompass all materials, the minimum temperature should be about -150°C.

1.4 This test method is intended for materials having an elastic modulus in the range of 0.5 MPa to 100 GPa.

1.5 Electronic instrumentation or automated data analysis and data reduction systems or treatments equivalent to this test method may also be used.

Note 1—The user bears the responsibility for determining the precision, accuracy, and validity of the techniques and measurements made using dynamic mechanical analyzers in accordance with this standard.

1.6 SI units are the standard.

1.7 This standard is similar to IEC 61006 except that standard uses the peak temprature of the mechanical loss peak as the glass transition temperature while this standard uses the extrapolated onset temperature of the loss modulus change.

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