ASTM D4273-23

5.1?The primary hydroxyl content provides information about the relative reactivities of polyols in the urethane forming reaction with isocyanates.

1.1?Carbon-13 Nuclear Magnetic Resonance Spectroscopy?(¹³C NMR) measures the primary hydroxyl content of ethylene oxide (EO)-propylene oxide (PO) polyether polyols used in preparing flexible polyurethane foams. This method is best suited for polyether polyols with primary hydroxyl contents of 10 to 90 %.

1.2?The values stated in SI units are to be regarded as standard.

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.