1、Designation: D 6979 03Standard Test Method forPolyurethane Raw Materials: Determination of Basicity inPolyols, Expressed as Percent Nitrogen1This standard is issued under the fixed designation D 6979; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method measures the basic constituents inpolyols that are soluble in glacial
3、acetic acid and reactive withperchloric acid. Samples containing 0.3 10 % nitrogen havebeen evaluated by this method. This test method is applicableto polyether polyols and polyether polyol blends that are usedin urethane reactions. (See Note 1.)1.2 This standard does not purport to address all of t
4、hesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.NOTE 1There is no equivalent ISO standard.2. Referenced Documents2.1
5、ASTM Standards:2D 883 Terminology Relating to PlasticsE 180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial ChemicalsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsFor definiti
6、ons of terms used in this testmethod see Terminology D 883.3.2 Definitions of Terms Specific to This Standard:3.2.1 percent nitrogenthe quantity of perchloric acid-titratable base, expressed as a weight percentage of nitrogen ina sample.4. Summary of Test Method4.1 The sample is dissolved in glacial
7、 acetic acid. Theresulting single-phase solution is titrated at room temperatureto a potentiometric end point with a standardized solution ofperchloric acid in acetic acid. Results are reported as percentnitrogen.5. Significance and Use5.1 This test method is suitable for quality control, as aspecif
8、ication test, and for research. The results are measures ofbatch-to-batch uniformity and may be useful in estimatingreactivity.5.1.1 The percent nitrogen can be used to characterize apolyol or indicate amounts of certain components in a polyolblend.5.1.2 It is permissible to also express the results
9、 in equiva-lents of base per gram of sample, if desired.6. Apparatus6.1 Potentiometric Automatic Titrator6.2 Autotitrator Buret with Dosing Device, 20-mL6.3 pH Glass Electrode and Reference Electrode or aCombination Glass Electrode6.4 Analytical Balances, capable of weighing to the nearest0.01g and
10、0.0001 g6.5 Magnetic Stirrer/Hotplate7. Reagents and Materials7.1 Purity of ReagentsUse reagent-grade chemicals in alltests. Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspe
11、cifications are available.3It is permissible to use othergrades provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Acetic Acid, Glacial7.3 Acetic Anhydride1This test method is under the jurisdiction
12、 of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular MaterialsPlastics and Elastomers.Current edition approved November 1, 2003. Published January 2004.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
13、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by
14、the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
15、ohocken, PA 19428-2959, United States.7.4 Perchloric Acid, (70 % nominal)7.5 Perchloric acid in Acetic Acid (0.10 N)Prepare 0.10 Nperchloric acid in acetic acid. For example, in a 1000-mLvolumetric flask dissolve 8.7 mL of perchloric acid in 500 mLof glacial acetic acid; add 25 mL of acetic anhydrid
16、e and diluteto volume with glacial acetic acid.NOTE 2Perchloric Acidis extremely irritating to the skin, eyes andmucous membrane; highly toxic via oral and inhalation routes; and canform explosive mixtures when mixed with carbonaceous material orallowed to dry. Concentrated material shall only be us
17、ed in a hoodapproved for perchloric acid use. Skin contactwash with soap and water.Eye contactflush with copious amounts of water for 15 minutes.Inhalation - move victim to an uncontaminated area. Ingestiondo notinduce vomiting. For all exposures seek professional medical advice.8. Procedure8.1 Weig
18、h the appropriate amount of sample, W into asuitable container. Calculate the target weight of sample to beanalyzed as follows:W 5 2/P (1)where:W = the target weight of the sample to be analyzed ingrams, andP = the expected percent nitrogen content of the sample.NOTE 3For sample weights below 10.0 g
19、 record the weight to thenearest 0.1 mg; for sample weights greater than 10.0 grams, record theweight to the nearest 0.01g.8.2 Add 100 mL of glacial acetic acid and gently stir untilthe sample dissolves completely.NOTE 4If necessary, the mixture can be heated gently until the sampleis completely di
20、ssolved.8.3 Titrate the sample solution potentiometrically with 0.10N perchloric acid through the end point which occurs at ca. 600mV.9. Calculation9.1 Calculate the basicity in the sample, as percent nitrogenas follows:% N 5S 3 N 3 14.00W 3 10003 100 % (2)where:S = the volume of titrant used to rea
21、ch the end point ofthe sample solution titration in millilitres,N = the normality of the 0.10 N perchloric acid solutionin milliequivalents per millilitre,W = the weight of the sample in grams,14.00 = the equivalent weight of nitrogen in milligrams permilliequivalent, and1000 = the factor for conver
22、ting milligrams to gramsNOTE 5It is permissible to also report the results as alkalinity inmilligrams of potassium hydroxide per gram of sample as follows:Alkalinity, mg KOH/g! 5S 3 N 3 56.10Wwhere:the variables have the same meaning as in 9.1 above and 56.10 is theequivalent weight of KOH in millie
23、quivalents per gram.10. Report10.1 For samples containing 1 % nitrogen or less, reportresults no more precisely than the nearest 0.0001 %.10.2 For samples containing between 1 and 10 %, reportresults no more precisely than the nearest 0.001 %.11. Precision and Bias411.1 Table 1 is based on a round r
24、obin involving sevenlaboratories and conducted in 2002 in accordance with PracticeE 180. All labs used potentiometric titration for the generationof the data used in this study. All the samples were prepared atone source, but the individual specimens were prepared at thelaboratories that tested them
25、 Each test result was the averageof two individual determinations. Each laboratory made dupli-cate determinations on each material on each of two days.11.2 PrecisionWarningThe following explanations of r and R (11.2.1-11.2.3) are intended only to present a meaningful way ofconsidering the approxima
26、te precision of this test method. Donot apply rigorously the data in Table 1 to the acceptance orrejection of material, as those data are specific to the roundrobin and may not be representative of other lots, conditions,materials, or laboratories. Users of this test method shouldapply the principle
27、s outlined in Practice E 180 or E 691 togenerate data specific to their laboratory and materials orbetween specific laboratories. The principles of 11.2.1-11.2.3then would be valid for such data.11.2.1 Repeatability, (r)Comparing two replicates for thesame material, obtained by the same operator, us
28、ing the sameequipment on the same day. The two replicate results shall bejudged not equivalent if they differ by more than the r value forthat material.11.2.2 Reproducibility, (R)Comparing two results, eachthe mean of replicates, for the same material, obtained bydifferent operators, using different
29、 equipment in differentlaboratories on different days. The two test results shall bejudged not equivalent if they differ by more than the R valuefor that material.11.2.3 Any judgment in accordance with 11.2.1 and 11.2.2would have an approximate 95 % (0.95) probability of beingcorrect.4Supporting dat
30、a have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D201239. The precision estimatesare based on an interlaboratory study performed in 2002 on four samples of polyolor polyol blend. Seven industrial laboratories participated in the test methodeva
31、luation.TABLE 1 Round-Robin Percent Nitrogen Data in Accordancewith Practice E 180AMaterial Average SrBSRCrDREdfFA 0.317 0.0007 0.0018 0.0020 0.0050 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 5AValues in units of percent nitrogen.BSr=
32、within-laboratory standard deviation of the replicates.CSR= between-laboratories standard deviation of the average.Dr = within-laboratory repeatability limit = 2.8Sr.ER = between-laboratories reproducibility limit = 2.8SR.Fdf = degrees of freedom in the data.D697903211.3 There are no recognized stan
33、dards by which to estimatethe bias of this test method.12. Keywords12.1 alkalinity; polyols; polyurethane; raw materials; testmethod; titrationASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of th
34、is 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 committee and must be reviewed every five ye
35、ars 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 meeting of theresponsible technical commi
36、ttee, 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 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).D6979033
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