ASTM D 2121 : 2000

1.1 These test methods cover the determination of the polymer content of styrene monomer and [alpha]-Methylstyrene (AMS). It should be noted, however, that dimers and trimers are not measured by these test methods.

1.2 Test Method A , which is based on the use of a spectrophotometer or photometer, is intended for the quantitative determination of the polymer content of styrene monomer or AMS in concentrations up to 15 mg/kg. Samples containing more than 15 mg/kg of polymer must be suitably diluted before measurement.

1.3 Test Method B is a rapid visual procedure that is intended for the approximate evaluation of polymer to a maximum concentration of 1.0 weight%. Samples having a polymer content of 1.0 weight% or greater should be suitably diluted prior to measurement.

1.4 The following applies to all specified limits in this standard: for purposes of determining conformance with this standard, an observed value or a calculated value shall be rounded off "to the nearest unit" in the last right-hand digit used in expressing the specification limit, in accordance with the rounding-off method of Practice E29.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of whoever uses this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 8.