Standard Test Method for Determination of the Linear Coefficient of Thermal Expansion of Plastic Lumber and Plastic Lumber Shapes Between –30 and 140°F (–34.4 and 60°C)

Importancia y uso:

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 applications for which plastic lumber and plastic lumber shapes are used, make –30 to 140°F (–34.4 to 60°C) a practical temperature range for linear thermal expansion measurements. 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 it is possible that special preliminary investigations by thermo-mechanical analysis, such as what is prescribed in Practice D4065 for the location of transition temperatures, will be required, in order to avoid excessive error. If such a transition point is located, a separate coefficient of expansion for a temperature range below and above the transition point shall be determined. For specification and comparison purposes (provided it is known that no transition exists in this range), the range from –30 to 140°F (–34.4 to 60°C) shall be used. (For reference, glass transition and melting point temperatures of typical resins used in plastic lumber products are given in Appendix X2 of this test method.)

Subcomité:

D20.20

Referida por:

D8484-23, D7031-11R19, D6662-22, D6117-23, D7568-23, D7258-23

Volúmen:

08.03

Número ICS:

17.040.99 (Other standards relating to linear and angular measurements), 83.140.99 (Other rubber and plastic products)

Palabras clave:

coefficient of expansion; linear expansion; plastic lumber; recycled plastics; thermal expansion;