ASTM E1640-13 Method for Assignment of the Glass Transition Temperature by Dynamic Mechanical Analysis

Scope:

The ASTM E1640-13 test method uses dynamic mechanical analyzers to determine the assignment of a glass transition temperature (Tg) of thermally stable materials in the glass transition region. Preferably, the materials have an elastic modulus in the range of 0.5 MPa to 100 GPa.

Test Procedure:

In ASTM E1640-13, a specimen of known geometry is placed in mechanical oscillation at either fixed or resonant frequency, and changes in the viscoelastic response of the material are monitored as a function of temperature. Under ideal conditions, during heating, the glass transition region is marked by a rapid decrease in the storage modulus and a rapid increase in the loss modulus and tangent delta. The glass transition of the test specimen is indicated by the extrapolated onset of the decrease in storage modulus, which marks the transition from a glassy to a rubbery solid.

Test Specimen:

Samples may be any uniform size or shape but are ordinarily analysed in rectangular form. Specimens measuring between 1 × 5 × 20 mm and 1 × 10 × 50 mm are suitable.

Data:

Calculate the glass transition temperature using the equation:

Where,

k = Predetermined Frequency Shift Factor 

F = Frequency of Measurement (Hz)

T = Glass Transition Temperature Observed at Frequency F (K)

T₁‘ = First Approximation for the Glass Transition Temperature at 1 Hz (K)

T₁ = Glass Transition Temperature at 1 Hz (K)

Read more: ASTM D5026 Determination of Dynamic Mechanical Properties of Plastic in Tension

Conclusion:

ASTM E1640-13 provides details about the test method for measuring the glass transition temperature using dynamic mechanical analysis.