ASTM D696-08
Standard Test Method for Coefficient of Linear Thermal Expansion of Plastics Between -30176C and 30176C With a Vitreous Silica Dilatometer
- Standard No.
- ASTM D696-08
- Release Date
- 2008
- Published By
- American Society for Testing and Materials (ASTM)
- Status
- Replace By
- ASTM D696-08e1
- Latest
- ASTM D696-16
- Scope
The coefficient of linear thermal expansion, α, between temperatures T1 and T2 for a specimen whose length is L 0 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.
The nature of most plastics and the construction of the dilatometer make −30 to +30°C (−22°F to +54°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 and special preliminary investigations by thermo-mechanical analysis, such as that prescribed in Practice D 4065
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 (54°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 1 × 10−6/°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.
Note 18212;There is no similar or equivalent ISO standard.
1.1.1 Test Method E 228
shall be used for temperatures other than −30°C to 30°C. 1.1.2 This test method shall not be used for measurements on materials having a very low coefficient of expansion (less than 1 × 10−6/°C). For materials having very low coefficient of expansion, interferome......
ASTM D696-08 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