5.1 This infrared absorbance method quantifies the total unsaturation structures in butyl rubber using the characteristic infrared absorbance regions and multivariate analysis. This method accounts for superimposing absorbances and is an extension of the typical method for infrared quantification, which correlates a single band absorbance height or area with concentration. This method measures the level of total unsat¬uration in butyl rubber by multivariate analysis Fourier Transform Infrared Spectroscopy. It is applicable for butyl rubber in the concentration range of 1.00 to 2.40 mol%. It can be expanded beyond these ranges with additional calibration RMs.

1.1 This test method covers the determination of the degree of unsaturation of butyl rubber as a molar percentage of the total sample. It is applicable to degrees of unsaturation from 1.00 to 2.40 mol% range.

1.2 The values stated in SI units of measurement are to be regarded as the standard. The values given in paratheses are for information only.

1.3 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 standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.