ASTM D696-16
Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between &x2212;30&xb0;C and 30&xb0;C with a Vitreous Silica Dilatometer

Standard No.

ASTM D696-16

Release Date

2016

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM D696-16

Scope

5.1 The coefficient of linear thermal expansion, α, between temperatures T₁ and T₂ for a specimen whose length is L₀ at the reference temperature, is given by the following equation:

where L₁ and L₂ are the specimen lengths at temperatures T₁ and T₂, respectively. α is, therefore, obtained by dividing the linear expansion per unit length by the change in temperature.

5.2 The nature of most plastics and the construction of the dilatometer make −30 to +30°C (−22°F to +86°F) a convenient temperature range for linear thermal expansion measurements of plastics. This range covers the temperatures in which plastics are most commonly used. Where testing outside of this temperature range or when linear thermal expansion characteristics of a particular plastic are not known through this temperature range, particular attention shall be paid to the factors mentioned in 1.2.

Note 2: In such cases, special preliminary investigations by thermo-mechanical analysis, such as that prescribed in Practice D4065 for the location of transition temperatures, may be required to avoid excessive error. Other ways of locating phase changes or transition temperatures using the dilatometer itself may be employed to cover the range of temperatures in question by using smaller steps than 30°C (86°F) or by observing the rate of expansion during a steady rise in temperature of the specimen. Once such a transition point has been located, a separate coefficient of expansion for a temperature range below and above the transition point shall be determined. For specification and comparison purposes, the range from −30°C to +30°C (−22°F to +86°F) (provided it is known that no transition exists in this range) shall be used.

1.1 This test method covers determination of the coefficient of linear thermal expansion for plastic materials having coefficients of expansion greater than 18201;µm/(m.°C) by use of a vitreous silica dilatometer. At the test temperatures and under the stresses imposed, the plastic materials shall have a negligible creep or elastic strain rate or both, insofar as these properties would significantly affect the accuracy of the measurements.

1.1.1 Test ......

ASTM D696-16 Referenced Document

• ASTM D4065 Standard Practice for Plastics: Dynamic Mechanical Properties: Determination and Report of Procedures
• ASTM D618 Standard Practice for Conditioning Plastics for Testing
• ASTM D883 Standard Terminology Relating to Plastics
• ASTM E228 Standard Test Method for Linear Thermal Expansion of Solid Materials With a Vitreous Silica Dilatometer
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM E831 Standard Test Method for Linear Thermal Expansion of Solid Materials by Thermomechanical Analysis

ASTM D696-16 history

• 2016 ASTM D696-16 Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between &x2212;30&xb0;C and 30&xb0;C with a Vitreous Silica Dilatometer
• 2008 ASTM D696-08e1 Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between −30°C and 30°C with a Vitreous Silica Dilatometer
• 2008 ASTM D696-08 Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between -30176C and 30176C With a Vitreous Silica Dilatometer
• 2003 ASTM D696-03 Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between -30176C and 30176C With a Vitreous Silica Dilatometer
• 1998 ASTM D696-98 Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between -30176C and 30176C With a Vitreous Silica Dilatometer