Materials undergo an increase in molecular mobility at the glass transition seen as a sigmoidal step increase in the heat capacity. This mobility increase may lead to kinetic events such as enthalpic recovery, chemical reaction or crystallization at temperatures near the glass transition. The heat flow associated with the kinetic events may interfere with the determination of the glass transition.

The glass transition is observed in differential scanning calorimetry as a sigmoidal or step change in specific heat capacity.

MTDSC provides a test method for the separation of the heat flow due to heat capacity and that associated with kinetic events making it possible to determine the glass transition in the presence of interfering kinetic event.

This test method is useful in research and development, quality assurance and control and specification acceptance.

Other methods for assigning the glass transition temperature include differential scanning calorimetry (Test Method E 1356), thermomechanical analysis (Test Method E 1545) and dynamic mechanical analysis (Test Method E 1640)

1. Scope

1.1 This test method describes the assignment of the glass transition temperature of materials using modulated temperature differential scanning calorimetry (MTDSC) over the temperature range from –120 to + 600 °C. The temperature range may be extended depending upon the instrumentation used.

1.2 SI units are the standard.

1.3 There are no ISO equivalents to this standard.

1.4 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.

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

E473 Terminology Relating to Thermal Analysis and Rheology

E967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal Analyzers

E968 Practice for Heat Flow Calibration of Differential Scanning Calorimeters

E1142 Terminology Relating to Thermophysical Properties

E1356 Test Method for Assignment of the Glass Transition Temperatures by Differential Scanning Calorimetry

E1545 Test Method for Assignment of the Glass Transition Temperature by Thermomechanical Analysis

E1640 Test Method for Assignment of the Glass Transition Temperature By Dynamic Mechanical Analysis

Keywords

cure; degree of cure; differential scanning calorimetry; glass transition temperature; modulated temperature differential scanning calorimetry; thermal analysis;

ICS Code

ICS Number Code 17.200.10 (Heat. Calorimetry)

Citing ASTM Standards

[Back to Top]