1、Designation: D3349 17Standard Test Method forAbsorption Coefficient of Ethylene Polymer MaterialPigmented with Carbon Black1This standard is issued under the fixed designation D3349; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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. Scope*1.1 This test method measures the amount of light transmit-ted through a film of carbon black pigmented ethyl
3、ene poly-mer.1.2 After calculation of the amount of light and filmthickness, an absorption coefficient is calculated.1.3 Whenever two sets of values are presented, in differentunits, the values in the first set are the standard, while those inparentheses are for information only.1.4 This standard do
4、es not purport to address all of thesafety 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.2. Referenced Documents2.1 ASTM Sta
5、ndards:2E60 Practice for Analysis of Metals, Ores, and RelatedMaterials by SpectrophotometryD1248 Specification for Polyethylene Plastics ExtrusionMaterials for Wire and Cable3. Summary of Test Method3.1 The transmission of light of a specified wavelengththrough thin ethylene polymer film is measure
6、d. The result isused to calculate an absorption coefficient that is a reciprocalfunction of transmission after correction for thickness.4. Significance and Use4.1 The absorption coefficient of polyolefin polymer pig-mented with carbon black is useful to judge the degree anduniformity of dispersion o
7、f the pigment, and the adequacy ofthe quantitative level of pigment addition. These factors areused to predict the performance of the polymer material inresponse to prolonged exposure to ultraviolet light as evi-denced by minimal changes in specific properties.NOTE 1This test method was developed to
8、 evaluate ethylene polymermaterials pigmented with small particle size carbon blacks suitable for UVprotection. It is not known how accurate and reproducible the test wouldbe with larger (35 nm or greater) particle size blacks.5. Apparatus5.1 SpectrophotometerAn instrument in accordance withPractice
9、 E60 is required.NOTE 2Consult the spectrophotometers operation manual or consultthe manufacturer of the instrument for the calibration procedure.5.2 MoldA mold in accordance with Figs. 1 and 2. Makethe mold of Ketos steel (or equivalent) hardened to RockwellC45, with mold surfaces chromium plated t
10、o 0.005-mm(0.0002-in.) minimum thickness.5.3 Specimen HolderCut two concentric rings fromphenolic-paper laminate or other suitable material to thedimensions shown in Fig. 3. Slip fit the rings snugly one withinthe other.5.4 Reference MaterialA reference material is requiredhaving an absorbance value
11、 of 1.0 to 1.2 at 375 nm asmeasured by the instrument used for testing.5.4.1 Neutral Density Filter,3M-type carbon 0.85 density,laminated between cellulose acetate sheets has been foundsatisfactory. Since this material is furnished as a rigid sheet, itcannot be mounted as described in Section 7. Ins
12、tead, a specialmount must be prepared by cutting Ring 1 of Fig. 3 in halfaround its circumference to give two rings about 2 mm(0.08 in.) thick. Cut a 22-mm (0.87-in.) circle from thelaminated filter, sandwich this between the two 2-mm rings,and slide the outer ring (Ring 2 of Fig. 3) over this compo
13、site.5.4.2 An alternative reference material can be prepared byany user of this test method. Prepare an alternative reference1This test method is under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.07 on El
14、ectrical Insulating Materials.Current edition approved March 1, 2017. Published March 2017. Originallyapproved in 1974. Last previous edition approved in 2012 as D3349 12. DOI:10.1520/D3349-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at se
15、rviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of the apparatus known to the committee at this timeis The Kodak neutral density filter, No. 5, available from the Eastman Kodak CoIf you are
16、 aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.*A Summary of Changes section appears at the end of this standardCopyright AST
17、M International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Stan
18、dards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1material consisting of a highly uniform sample of ASTM TypeI polyethylene (see Specification D1248) containing about 1 %of a 20-nm carbon black (either channel or furnace type). Pres
19、sout a uniform film of this material and mount as in Section 8to meet the above requirements. Reference materials so pre-pared shall show no more than 6 4 % variation from theaverage absorbance value when measured at any point at375 nm in the instrument used for testing.6. Calibration and Standardiz
20、ation6.1 Allow the spectrophotometer to stabilize. Using thespectrophotometer manufacturers instructions, set the zeroand infinity values on the absorbance scale.6.2 Insert the mounted reference material in the spectropho-tometer and place it into the light beam. Read and record theabsorbance value
21、using the conditions that bring the valuenearest to zero on the absorbance scale. With the referencematerial still in the beam, readjust the slit width to bring thereading back to zero. Recheck the infinity value.7. Conditioning7.1 No special conditioning is required.8. Specimen Preparation8.1 Prepa
22、re three test specimens from each lot of materialby hot-pressing the ethylene polymer at a suitable temperaturebetween highly polished plates, such as those shown in Figs. 1and 2, using a charge sufficient to yield a specimen 40 to 50mm in diameter and approximately 0.01 mm in thickness.Double press
23、ing expedites the preparation of satisfactoryspecimens, that is, pressing to approximately 0.05 mm thick-ness and then pressing a section of that sheet to the required0.01 mm thickness. Use of a silicone mold release agent is alsorecommended. For each specimen in turn, carefully transfer thespecimen
24、 to the inner ring of the specimen holder (Ring 1, Fig.3). With the specimen positioned concentrically over the innerring, carefully press the outer ring (Ring 2, Fig. 3) down overit to complete the mounting operation. Mount the specimenfirmly, taut, and wrinkle-free. Visually examine the mountedFIG
25、. 1 Mold, Top PlatenD3349 172test specimen against a suitable light source. It must be uniformin color and free of clear spots or holes. Mark and identifythree points approximately 120 apart on the outer ring of eachspecimen.9. Procedure9.1 Bring the first mounted specimen into measuring posi-tion u
26、sing the remaining outer position of the specimen holder,keeping the specimen as close to the receiver as possible.Position the specimen with one of the 120 marks at the top.Open the shutter, read and record the absorbance value v1. Theabsorbance value recorded is equal to that indicated on themeter
27、 plus the measured value for the reference material.9.2 Close the shutter and recheck the reference material.Rotate the specimen to bring the next 120 mark to the top andobtain the absorbance value v2. Repeat the procedure with thethird 120 mark at the top to obtain the value v3. Average thevalues v
28、1,v2, and v3to obtain the average absorbance v.Ifanyvalue of v differs from v by more than 10 %, discard thespecimen and replace it.9.3 Remove the film from the specimen mounting rings bycutting it carefully along the boundary between the two ringsand weigh it to the nearest 0.0001 g. The No. 11 Bar
29、d-Parkerscalpel blade4in a suitable handle has been found veryeffective for the cutting operation. Measure the diameter andcalculate the area of the specimen. Calculate average specimenthickness as follows:t 5 1022W!/DA! (1)where:t = thickness, m,W = weight, g,D = density, g/cm3, andA = area, cm2.NO
30、TE 3The nominal density value for black low density ethylenepolymer is 0.923 g/cm3.9.4 Repeat 9.1 9.3 for the second and third specimens.10. Calculation10.1 Calculate the absorption coefficient of each specimen,in turn, as follows:4The sole source of supply of the apparatus known to the committee at
31、 this timeis the No. 11 Bard-Parker scalpel blade, available from most laboratory supplyhouses. If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical co
32、mmittee,1which you may attend.FIG. 2 Mold, Bottom PlatenD3349 173a 5 10232.303v!/t! (2)where:a = absorption coefficient, 1000 (absorbance/metre), at375 nm,v = average absorbance as found in 9.2, andt = thickness, m, as found in 9.3.10.2 Average the three values, a, for the three specimens toobtain t
33、he value for the sample.11. Report11.1 Report the following:11.1.1 Complete identification of the material tested,11.1.2 Nominal density of the material tested,11.1.3 Calculated absorption coefficient of each specimentested,11.1.4 Average absorption coefficient of three specimenstested, which is the
34、 value for the sample, and11.1.5 Type and model of spectrophotometer used.11.1.6 Date of test11.1.7 Name of operator12. Precision and Bias12.1 Precision:12.1.1 In the early 1970s, a round-robin study was con-ducted by five laboratories using one sample of carbonblack-pigmented ethylene polymer and t
35、he same make andmodel of spectrophotometer. Each laboratory molded from twoto five test specimens from the sample and determined theabsorption coefficient of each. The following statistics, eachexpressed in the units of 1000 (absorbance/metre), werederived from the data submitted for this one sample
36、.Mean = 443Sr=24SR=4312.1.2 Interpretation of the data for the intervals Srand SRgiven above are as follows.NOTE 1If required, adjust either the inside diameter of Ring 2 or outside diameter of Ring 1 to obtain a snug fit of pressed film.FIG. 3 Specimen Mounting RingsD3349 17412.1.2.1 RepeatabilityI
37、n comparing two averages (ofthree specimens each) for the sample obtained in one labora-tory by one operator on the same day, the averages are judgedas not equivalent if they differ by more than Sr.12.1.2.2 ReproducibilityIn comparing two averages (ofthree specimens each) for the sample obtained in
38、differentlaboratories by different operators on different days, the aver-ages are judged as not equivalent if they differ by more than SR.12.1.2.3 The judgments in 12.1.2.1 and 12.1.2.2 will becorrect in approximately 95 % of such comparisons.12.2 Bias:12.2.1 In the round-robin study, it was found t
39、hat differentmakes and models of spectrophotometer can produce system-atically different results for the average absorbance of aspecimen, with the maximum consistent difference being 6 %relative for the four types of instrument used in the study.12.2.2 In critical applications, such as conformance o
40、f amaterial to a specification, it is necessary for the buyer andseller to agree upon the instrument that is to be used or toestablish a correlation between the two types of instruments inuse.13. Keywords13.1 absorption coefficient; carbon black; ethylene polymerSUMMARY OF CHANGESCommittee D09 has i
41、dentified the location of selected changes to this standard since the last issue(D3349 12) that may impact the use of this standard. (Approved March 1, 2017.)(1) The density of low density polyethylene was corrected to0.923 g cm, based upon Test Method D1238.(2) Spelling of spectrophotometer was cor
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43、nt 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 years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or
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