ASTM E2008-07

Volatility of a material is not an equilibrium thermodynamic property but is a characteristic of a material related to a thermodynamic property that is vapor pressure. It is influenced by such factors as surface area, temperature, particle size, and purge gas flow rate; that is, it is diffusion controlled.

The extent of containment achieved for specimens in this test method by means of a pinhole opening between 0.33 to 0.38 mm allows for measurement circumstances that are relatively insensitive to experimental variables other than temperature. Decreasing the extent of containment by use of pinholes larger than 0.38 mm will increase the magnitude of the observed rate of mass loss but will also reduce the measurement precision by increasing the sensitivity to variations in other experimental variables.

Results obtained by this test method are not strictly equivalent to those experienced in processing or handling conditions but may be used to rank materials for their volatility in such circumstances. Therefore, the volatility rates determined by this test method should be considered as index values only.

The volatility rate may be used to estimate such quantifiable values as drying interval or the extent of volatile release from a process.

1.1 This test method covers procedures for assessing the volatility of solids and liquids at given temperatures using thermogravimetry under prescribed experimental conditions. Results of this test method are obtained as volatility rates expressed as mass per unit time. Rates 5 g/min are achievable with this test method.

1.2 Temperatures typical for this test method are within the range from 25°C to 500°C. This temperature range may differ depending upon the instrumentation used.

1.3 This test method is intended to provide a value for the volatility rate of a sample using a thermogravimetric analysis measurement on a single representative specimen. It is the responsibility of the user of this test method to determine the need for and the number of repetitive measurements on fresh specimens necessary to satisfy end use requirements.

1.4 Computer- or electronic-based instruments, techniques, or data treatment equivalent to this test method may also be used.

Users of this test method are expressly advised that all such instruments or techniques may not be equivalent. It is the responsibility of the user of this test method to determine the necessary equivalency prior to use.

1.5 SI units are the standard.

1.6 There is no ISO method equivalent to this standard.

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 test method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.