ASTM D4671-05(2010)e1

These test methods are suitable for quality control, as specification tests, and for research.

Side reactions that form unsaturated compounds in polypropylene oxides produce small amounts of polymers with only one hydroxyl group per chain. These unsaturated polymers lower functionality and molecular weight, while broadening the overall molecular-weight distribution.

1.1 These test methods measure unsaturation in polyether polyols. (See Note 1.)

1.1.1 Test Method A, High-Volume Reagent Method—Uses about 50 mL of 0.1 M mercuric acetate reagent in methanol and 15 g or more of sample. These test methods use an indicator for colorimetric determination of an end point. It is recommended for polyols with low values (below 0.01 millequivalents per gram (meq/g)) of unsaturation where large sample sizes are required.

1.1.2 Test Method B, Low-Volume Reagent Method—Uses 2 mL of ca. 0.05 M mercuric acetate reagent in methanol and about 1 g of sample or less. These test methods use a potentiometric determination of an end point.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 and health practices and determine the applicability of regulatory limitations prior to use.

Note 1—There is no known ISO equivalent to this standard.