ASTM D7426-08

Differential scanning calorimetry provides a rapid test method for determining changes in specific heat capacity in a homogeneous material or domain. The glass transition is manifested as a step change in specific heat capacity. For amorphous and semi-crystalline materials the determination of the glass transition temperature may lead to important information about their thermal history, processing conditions, stability of phases, and progress of chemical reactions.

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

1.1 This test method covers the assignment of the glass transition temperatures (T_g) of materials using differential scanning calorimetry.

1.2 This test method is applicable to amorphous materials, including thermosets or semicrystaline materials containing amorphous regions, that are stable and do not undergo decomposition or sublimation in the glass transition region.

1.3 The normal operating temperature range is from –120 to 500°C. The temperature range may be extended, depending upon the instrumentation used.

1.4 Computer or electronic-based instruments, techniques, or data treatment equivalent to this test method may also be used.

Note 1—Users of this test method are expressly advised that all such instruments or techniques may not be equivalent. It is the responsibility of the user of this standard to determine the necessary equivalency prior to use.

1.5 ISO 11357–2 is equivalent to this test method.

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

1.7 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.