This practice covers infrared spectrophotometry procedures for determining the molecular structural features such as types and number of branches in polyolefins and polyolefin copolymers. The structural features expressed by these determinations affect the ultimate polymeric properties and are useful in showing correlations with many performance properties. The apparatus is comprised of double beam or Fourier transform infrared spectrophotometer, hot plate, microscope slides, compression molding press, metal plates, brass shims, micrometer, and film mounts. Materials shall include polyethylene terephthalate, aluminum, or matte finished teflon-fiberglass sheet. The concentration shall be calculated using either the Beer-Lambert law with the appropriate molar absorptivity or an appropriate calibration curve.

1.1 This practice covers infrared procedures for determining the molecular structural features in polyolefins and polyolefin copolymers. The structural features of primary concern are the types and numbers of branches. Although this practice centers its attention on polyolefins and polyolefin copolymers, the techniques, with proper modification, can be used for some other polymers as well.

Note 1: Quantitative determinations require either an internal or an external evaluation of sample thickness. ASTM test methods available for specific features are listed in Tables 1 and 2.

1.2 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.

Note 2: There is no known ISO equivalent to this standard.

1.3 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.