ASTM D2839-2016 Standard Practice for Use of a Melt Index Strand for Determining Density of Polyethylene《用绞线熔融指数测定聚乙烯密度的规程》.pdf
《ASTM D2839-2016 Standard Practice for Use of a Melt Index Strand for Determining Density of Polyethylene《用绞线熔融指数测定聚乙烯密度的规程》.pdf》由会员分享,可在线阅读,更多相关《ASTM D2839-2016 Standard Practice for Use of a Melt Index Strand for Determining Density of Polyethylene《用绞线熔融指数测定聚乙烯密度的规程》.pdf(2页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: D2839 16Standard Practice forUse of a Melt Index Strand for Determining Density ofPolyethylene1This standard is issued under the fixed designation D2839; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 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 practice covers the preparation of a sample forpolyethylene density determination in accordance with TestMethod D150
3、5. The sample consists of a strand produced byextrusion of the polyethylene in accordance with Test MethodD1238, Condition 190/2.16 (Melt Index).1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not pur
4、port 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.NOTE 1There is no known ISO equivalent to thi
5、s standard.NOTE 2The precision data on densities measured using this samplepreparation practice is listed in Test Method D1505.2. Referenced Documents2.1 ASTM Standards:2D1238 Test Method for Melt Flow Rates of Thermoplasticsby Extrusion PlastometerD1505 Test Method for Density of Plastics by the De
6、nsity-Gradient TechniqueD4703 Practice for Compression Molding ThermoplasticMaterials into Test Specimens, Plaques, or Sheets3. Terminology3.1 Definitions:3.1.1 melt index strandthe extrudate produced when poly-ethylene is extruded in accordance with Test Method D1238,Condition 190/2.16.4. Significa
7、nce and Use4.1 This practice has been found to be very useful forpreparing polyethylene samples suitable for determination ofdensity by Test Method D1505, for quality control purposes,especially in a resin manufacturing facility where fast,reproducible, comparative results are needed. It is not nece
8、s-sarily recommended for resin specifications that are part of asales contract between the buyer and the seller.4.2 The density of a polyethylene sample is highly depen-dent on the preparation and thermal history of the specimens.The level of density results obtained by this practice of sampleprepar
9、ation differs from that obtained by other methods asdescribed in Practice D4703, Annex A1.4.3 Before proceeding with this practice, reference shall bemade to the specification of the material being tested. Any testspecimen preparation, conditioning, dimensions, or testingparameters, or some combinat
10、ion thereof, covered in thematerials specification shall take precedence over those men-tioned in this practice. If there are no material specifications,the default conditions apply.5. Apparatus5.1 Extrusion Plastometer, as described in Test MethodD1238.5.2 Hot Plate, to boil water.5.3 Beakers, 250-
11、mL low form, graduated, with watch-glasscovers.6. Sample6.1 Polyethylene, in any form suitable for test in accordancewith Test Method D1238.7. Procedure7.1 Prepare a Melt Index Strand by extruding the sample inaccordance with Test Method D1238, Condition 190/2.16,dropping the strand on a cool metal
12、plate after cutting off.When Procedure B of Test Method D1238 is used, cut off theextrudate at about the time the timer is actuated and discard.Save the portion extruded during the timed interval.NOTE 3It has been shown that the measured density of an extruded1This practice is under the jurisdiction
13、 ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials(D20.15.01).Current edition approved Oct. 1, 2016. Published October 2016. Originallyapproved in 1969. Last previous edition approved in 2010 as D2839 - 10. DOI:10.1520/D2839-16.2For re
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