1、Designation: D6979 08D6979 13Standard Test Method forPolyurethane Raw Materials: Determination of Basicity inPolyols, Expressed as Percent Nitrogen1This standard is issued under the fixed designation D6979; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method measures the basic constituents in polyols that are soluble in gl
3、acial acetic acid and reactive with perchloricacid. Samples containing 0.3 10 % nitrogen have been evaluated by this method. This test method is applicable to polyetherpolyols and polyether polyol blends that are used in urethane reactions. (See Note 1.)1.2 The values stated in SI units are to be re
4、garded 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 responsibilityof the user of this standard to establish appropriate safety and health practices and det
5、ermine the applicability of regulatorylimitations prior to use.NOTE 1This standard is equivalent to ISO 25761:082. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsE180 Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Speci
6、alty Chemicals(Withdrawn 2009)3E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 DefinitionsFor definitions of terms used in this test method see Terminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 percent nitroge
7、nthe quantity of perchloric acid-titratable base, expressed as a weight percentage of nitrogen in a sample.4. Summary of Test Method4.1 The sample is dissolved in glacial acetic acid. The resulting single-phase solution is titrated at room temperature to apotentiometric end point with a standardized
8、 solution of perchloric acid in acetic acid. Results are reported as percent nitrogen.5. Significance and Use5.1 This test method is suitable for quality control, as a specification test, and for research. The results are measures ofbatch-to-batch uniformity and may be are useful in estimating react
9、ivity.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 equivalents of base per gram of sample, if desired.6. Apparatus6.1 Potentiometric Automatic Titrator6.2 Autotitrato
10、r Buret with Dosing Device, 20-mL1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plasticsand Elastomers.Current edition approved Aug. 1, 2008Nov. 1, 2013. Published September 2008November 2
11、013. Originally approved in 2003. Last previous edition approved in 20032008as D6979 - 03.D6979 - 08. DOI: 10.1520/D6979-08.10.1520/D6979-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume
12、information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have be
13、en made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official documen
14、t.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.3 pH Glass Electrode and Reference Electrode or a Combination Glass Electrode6.4 Analytical Balances, capable of weighing to the nearest 0.01g and 0.0001 g6.5 Magnetic Stirrer/Hotpla
15、te7. Reagents and Materials7.1 Purity of ReagentsUse reagent-grade chemicals in all tests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are available.4 It is
16、 permissible to use other grades provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy of the determination.7.2 Acetic Acid, Glacial7.3 Acetic Anhydride7.4 Perchloric Acid, (70 % nominal)7.5 Perchloric acid in Acetic Acid (0.
17、10 N)Prepare 0.10 N perchloric acid in acetic acid. For example, in a 1000-mLvolumetric flask dissolve 8.7 mL of perchloric acid in 500 mL of glacial acetic acid; add 25 mL of acetic anhydride and dilute tovolume with glacial acetic acid.NOTE 2Perchloric Acidis extremely irritating to the skin, eyes
18、 and mucous membrane; highly toxic via oral and inhalation routes; and can formexplosive mixtures when mixed with carbonaceous material or allowed to dry. Concentrated material shall only be used in a hood approved for perchloricacid use. Skin contactwash with soap and water. Eye contactflush with c
19、opious amounts of water for 15 minutes. Inhalation - move victim to anuncontaminated area. Ingestiondo not induce vomiting. For all exposures seek professional medical advice.8. Procedure8.1 Weigh the appropriate amount of sample, W into a suitable container. Calculate the target weight of sample to
20、 be analyzedas follows:W52/P (1)where:W = the target weight of the sample to be analyzed in grams, andP = the expected percent nitrogen content of the sample.NOTE 3For sample weights below 10.0 g, record the weight to the nearest 0.1 mg; for sample weights greater than 10.0 g, record the weight to t
21、henearest 0.01g.8.2 Add 100 mL of glacial acetic acid and gently stir until the sample dissolves completely.NOTE 4If necessary, the mixture can be heated gently until the sample is completely dissolved.8.3 Titrate the sample solution potentiometrically with 0.10 N perchloric acid through the end poi
22、nt which occurs at ca. 600 mV.9. Calculation9.1 Calculate the basicity in the sample, as percent nitrogen as follows:%N 5S 3N 314.00W 31000 3100% (2)where:S = the volume of titrant used to reach the end point of the sample solution titration in millilitres,N = the normality of the 0.10 N perchloric
23、acid solution in milliequivalents per millilitre,W = the weight of the sample in grams,14.00 = the equivalent weight of nitrogen in milligrams per milliequivalent, and1000 = the factor for converting milligrams to gramsNOTE 5It is permissible to also report the results as alkalinity in milligrams of
24、 potassium hydroxide per gram of sample as follows:Alkalinity,mg KOH/g! 5S 3N 356.10Wwhere:the variables have the same meaning as in 9.1 above and 56.10 is the equivalent weight of KOH in mg per meq.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington,
25、 DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D6979 13210. R
26、eport10.1 For samples containing 1 % nitrogen or less, report results no more precisely than the nearest 0.0001 %.10.2 For samples containing between 1 and 10 %, report results no more precisely than the nearest 0.001 %.11. Precision and Bias511.1 Table 1 is based on a round robin involving seven la
27、boratories and conducted in 2002 in accordance with Practice E180.All labs used potentiometric titration for the generation of the data used in this study.All the samples were prepared at one source,but the individual specimens were prepared at the laboratories that tested them. Each test result was
28、 the average of two individualdeterminations. Each laboratory made duplicate determinations on each material on each of two days. (WarningThe explanationof r and R (11.2.1 11.2.3) are only intended to present a meaningful way of considering the approximate precision of this testmethod. The data in T
29、able 1 should not be applied to acceptance or rejection of material, as these data apply only to the materialstested in the round robin and are unlikely to be rigorously representative of other lots, formulations, conditions, materials, orlaboratories. Users of this test method should apply the prin
30、ciples outlined in Practice E180 or E691 to generate data specific totheir materials and laboratory (or between specific laboratories). The principles of 11.2.1 11.2.3 would then be valid for suchdata.)11.2 PrecisionWarningThe following explanations of r and R (11.2.1 11.2.3) are intended only to pr
31、esent a meaningful way of consideringthe approximate precision of this test method. Do not apply rigorously the data in Table 1 to the acceptance or rejection of material,as those data are specific to the round robin and may not be representative of other lots, conditions, materials, or laboratories
32、. Usersof this test method should apply the principles outlined in Practice E180 or E691 to generate data specific to their laboratory andmaterials or between specific laboratories. The principles of 11.2.1 11.2.3 then would be valid for such data.11.2.1 Repeatability, (r)Comparing two replicates fo
33、r the same material, obtained by the same operator, using the sameequipment on the same day. The two replicate results shall be judged not equivalent if they differ by more than the r value for thatmaterial.11.2.2 Reproducibility, (R)Comparing two results, each the mean of replicates, for the same m
34、aterial, obtained by differentoperators, using different equipment in different laboratories on different days. The two test results shall be judged not equivalentif they differ by more than the R value for that material.11.2.3 Any judgment in accordance with 11.2.1 and 11.2.2 would have an approxim
35、ate 95 % (0.95) probability of being correct.11.3 There are no recognized standards by which to estimate the bias of this test method.5 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D20-1239. The precision estimates arebased o
36、n an interlaboratory study performed in 2002 on four samples of polyol or polyol blend. Seven industrial laboratories participated in the test method evaluation.TABLE 1 Round-Robin Percent Nitrogen Data in Accordance withPractice E180AMaterial Average SrB SRC rD RE dfFA 0.317 0.0007 0.0018 0.0020 0.
37、0050 5B 2.51 0.0046 0.0053 0.0129 0.0148 5C 5.86 0.0079 0.0139 0.0221 0.0392 5D 9.45 0.0220 0.0217 0.0616 0.0618 5TABLE 1 Round-Robin Percent Nitrogen Data in Accordance withPractice E180AMaterial Average SrB SRC rD RE dfFA 0.317 0.0007 0.0018 0.0020 0.0050 5B 2.51 0.0046 0.0053 0.0129 0.0148 5C 5.8
38、6 0.0079 0.0139 0.0221 0.0392 5D 9.45 0.0220 0.0217 0.0616 0.0618 5A Values in units of percent nitrogen.BSr = within-laboratory standard deviation of the replicates.CSR = between-laboratories standard deviation of the average.Dr = within-laboratory repeatability limit = 2.8Sr.ER = between-laborator
39、ies reproducibility limit = 2.8SR.F df = degrees of freedom in the data.D6979 13312. Keywords12.1 alkalinity; nitrogen; polyols; polyurethane; raw materials; test method; titrationASTM International takes no position respecting the validity of any patent rights asserted in connection with any item m
40、entionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committ
41、ee and must be reviewed every five years andif not revised, either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeti
42、ng of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO
43、 Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D6979 134
