ASTM D6979-2018 pdf free download
ASTM D6979-2018 pdf free download.Standard Test Method for Polyurethane Raw Materials: Determination of Basicity in Polyols, Expressed as Percent Nitrogen
1. Scope
1.1 This test method measures the basic constituents in polyols that are soluble in glacial acetic acid and reactive with perchloric acid. Samples containing 0.3 – 10 % nitrogen have been evaluated by this method. This test method is applicable to polyether polyols and polyether polyol blends that are used in urethane reactions. (See Note 1.) 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. N OTE 1—This standard is equivalent to ISO 25761:08. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions—For definitions of terms used in this test method see Terminology D883. 3.2 Definitions ofTerms Specific to This Standard: 3.2.1 percent nitrogen—the quantity of perchloric acid- titratable base, expressed as a weight percentage of nitrogen in a sample.
4. Summary of Test Method
4.1 The sample is dissolved in glacial acetic acid. The resulting single-phase solution is titrated at room temperature to a potentiometric end point with a standardized solution of perchloric acid in acetic acid. Results are reported as percent nitrogen.
5. Significance and Use
5.1 This test method is suitable for quality control, as a specification test, and for research. The results are measures of batch-to-batch uniformity and are useful in estimating reactiv- ity. 5.1.1 The percent nitrogen can be used to characterize a polyol or indicate amounts of certain components in a polyol blend. 5.1.2 It is permissible to also express the results in equiva- lents of base per gram of sample, if desired.
6. Apparatus
6.1 Potentiometric Automatic Titrator 6.2 Autotitrator Buret with Dosing Device, 20-mL 6.3 pH Glass Electrode and Reference Electrode or a Combination Glass Electrode 6.4 Analytical Balances, capable ofweighing to the nearest 0.01g and 0.0001 g 6.5 Magnetic Stirrer/Hotplate
7. Reagents and Materials
7.1 Purity ofReagents—Use reagent-grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such specifications are available. 5 It is permissible to use other grades provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. 7.2 Acetic Acid, Glacial 7.3 Acetic Anhydride 7.4 Perchloric Acid, (70 % nominal) 7.5 Perchloric acid in Acetic Acid (0.10 N)—Prepare 0.10 N perchloric acid in acetic acid. For example, in a 1000-mL volumetric flask dissolve 8.7 mL of perchloric acid in 500 mL of glacial acetic acid; add 25 mL of acetic anhydride and dilute to volume with glacial acetic acid. N OTE 2—Perchloric Acid—is extremely irritating to the skin, eyes and mucous membrane; highly toxic via oral and inhalation routes; and can form explosive mixtures when mixed with carbonaceous material or allowed to dry. Concentrated material shall only be used in a hood approved for perchloric acid use. Skin contact—wash with soap and water. Eye contact—flush with copious amounts of water for 15 minutes. Inhalation – move victim to an uncontaminated area. Ingestion—do not induce vomiting. For all exposures seek professional medical advice.
