1、Designation: D5885/D5885M 15D5885/D5885M 17Standard Test Method forOxidative Induction Time of Polyolefin Geosynthetics byHigh-Pressure Differential Scanning Calorimetry1This standard is issued under the fixed designation D5885/D5885M; the number immediately following the designation indicates theye
2、ar of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a procedure for the determina
3、tion of the oxidative induction time (OIT) of polyolefin geosyntheticsusing high pressure high-pressure differential scanning calorimetry.1.2 The focus of the test is on geomembranes, but geogrids, geonets, geotextiles, and other polyolefin-related geosynthetics arealso suitable for such evaluation.
4、1.3 This test method measures the oxidative induction time associated with a given test specimen at a specified temperature andpressure.1.4 This is an accelerated test for highly stabilized materials. It is applicable only to material whose OIT values under 3.4 MPa3.4 MPa of oxygen is greater than 3
5、0 min at 150C.150 C.1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result i
6、n non-conformance with the standard.1.6 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 determine the applicability of regulatorylimita
7、tions prior to use. Specific precautionary statements are given in Section 8.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and R
8、ecommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3895 Test Method for Oxidative-Induction Time of Polyolefins by Differential Scanning CalorimetryD4439 Terminology for GeosyntheticsD4491D4491/D4491M Test Meth
9、ods for Water Permeability of Geotextiles by PermittivityD4565 Test Methods for Physical and Environmental Performance Properties of Insulations and Jackets for TelecommunicationsWire and CableD4703 Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or SheetsE473
10、Terminology Relating to Thermal Analysis and RheologyE967 Test Method for Temperature Calibration of Differential Scanning Calorimeters and Differential Thermal AnalyzersE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE967 Test Method for Temperature
11、Calibration of Differential Scanning Calorimeters and Differential Thermal AnalyzersG88 Guide for Designing Systems for Oxygen Service3. Terminology3.1 Definitions:3.1.1 For definitions of terms related to geosynthetics, refer to Terminology D4439.1 This test method is under the jurisdiction of ASTM
12、 Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.02 on Endurance Properties.Current edition approved May 1, 2015June 1, 2017. Published June 2015June 2017. Originally approved in 1995. Last previous edition approved in 20122015 asD5885 06 (2012).D5885/D5885M 15. D
13、OI: 10.1520/D5885_D5885M-15.10.1520/D5885_D5885M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This docu
14、ment is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been 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
15、appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.2 Definitions of terms applying to thermal analysis a
16、ppear in Terminology E473.3.2 Definitions:Definitions of Terms Specific to This Standard:3.2.1 differential scanning calorimetry (DSC), na technique in which the difference in heat flow inputs into a substance anda reference material is measured as a function of temperature or time, while the substa
17、nce and reference material are subjected toa controlled-temperature program. (See Terminology E473.)3.2.2 geomembrane, nan essentially impermeable geosynthetic composed of one or more synthetic sheets. (See TerminologyD4439.)3.2.2.1 DiscussionIn this test method, essentially impermeable means that n
18、o measurable liquid flows through a geosynthetic when tested inaccordance with Test Methods D4491D4491/D4491M.3.2.3 geosynthetic, na planar product manufactured from polymeric material used with soil, rock, earth, or other geotechnicalengineering-related material as an integral part of a man-made pr
19、oject, structure, or system. (See Terminology D4439.)3.2.4 high-pressure differential scanning calorimetry (HPDSC), ndifferential scanning calorimetry in which the substance andreference material are exposed to a controlled superambient atmosphere.3.2.5 index test, na test procedure that may be used
20、 to establish an order for a set of specimens with respect to the propertyof interest.3.2.6 oxidative induction time (OIT), nthe elapsed time between first exposure to an oxidizing gas and the onset to oxidationof a material under isothermal conditions.3.2.6.1 DiscussionOxidative induction time is a
21、n index test parameter dependent upon a wide range of experimental conditions including temperature,pressure of oxygen, purge gas flow rate, and the presence or absence of catalysts.4. Summary of Test Method4.1 The specimen to be tested and the corresponding reference material are is heated from roo
22、m temperature at a constant ratein a non-purging, high-pressure oxygen environment at a defined pressure. When the specified temperature has been reached, thespecimen is then held at that temperature until the oxidative reaction is displayed on the thermal curve. The OIT is the time intervalfrom the
23、 start of the temperature program test to the onset of the oxidative reaction.4.2 In this procedure, an elevated pressure of oxygen is used to accelerate the reaction and to reduce analysis time.4.3 Unless otherwise specified, the temperature used in this test method shall be 150C,150 C, and the cha
24、mber pressure is tobe maintained at 3.4 MPa 500 psi using a constant volume test condition.5. Significance and Use5.1 The oxidative induction time is a characteristic of a compounded polyolefin product that is dependent not only on the typeand amount of additives present, but also on the type of res
25、in. In well-behaved systems, this test method can be used as a qualitycontrol measure to monitor the stabilization in geosynthetics as received from a supplier.5.2 When this test method is used to compare different geomembrane formulations containing different antioxidant packages,then those results
26、 shall be considered valid only at the temperature of test.5.3 This test method is intended as ana geosynthetic test. Use of the OIT value to estimate the lifetime of the geomembrane fromwhich the test specimen is taken is not addressed, nor shall it be used for this purpose.5.3.1 The OIT measuremen
27、t is an accelerated thermal aging test and, as such, interpretation of resulting data may be misleadingif done by an inexperienced operator. Caution should be exercised in data interpretation since oxidation reaction kinetics are afunction of temperature and the properties of the additives contained
28、 in the geosynthetic sample. For example, OIT values are oftenused to select optimum resin formulations. Certain antioxidants, however, may generate poor OIT results even though they maybe adequate at their intended use temperature and vice versa.5.4 This test method can be used for other purposes s
29、uch as manufacturing control and research and development.5.5 Oxidation induction time is strongly dependent upon test temperature and the partial pressure of oxygen. The higher the testtemperature or the oxygen partial pressure, or both, the shorter the oxidation induction time.5.5.1 The use of hig
30、h test temperature, however, may have deleterious effects. The first of these is the potential volatilizationof additive packages used to stabilize the test materials.The second is the potential for the influence of chemical mechanisms whichare not significant at end-use operation conditions.D5885/D
31、5885M 1725.5.2 This test method uses high oxygen pressure to accelerate the test period while making use of lower test temperatures toprotect additive packages.5.6 The results from this test method may or may not correlate with those obtained by other OIT measurements such as TestMethod D3895 or Tes
32、t Methods D4565.6. Apparatus6.1 Differential Scanning CalorimeterThermal analysis equipment capable of heating rates up to 20 6 1C/min1 Cmin andof automatically recording the differential heat flow between the test sample and a reference sample is necessary. The equipmentmust be capable of measuring
33、 sample temperature to 61C61 C while maintaining a set temperature to 60.5C.60.5 C.NOTE 1Modern computer-based instrumentation equipped with “iso-track” modes provideprovides adequate specimen temperature control.6.2 Data Presentation Data-Presentation DeviceA printer, plotter, recorder, or other re
34、cording output device capable ofdisplaying heat flow on the Yy-axis versus time on the Xx-axis as output signals from differential scanning calorimeters in 6.1.6.3 High-Pressure DSC CellA unit capable of maintaining pressure up to 3.4 MPa 500 psig. The system shall be equippedwith a pressure gage to
35、 monitor the internal pressure of the cell to permit manual release of pressure to maintain desired level.NOTE 2The gage shall be accurate to 2 % at 3.4 MPa 500 psig.NOTE 3All pressures in this test method are indicated relative to atmosphere pressurethat is, they are “gage” pressures.6.4 High-Press
36、ure Oxygen Cylinder RegulatorA pressure regulator capable of regulating a pressure up to 5.5 MPa 800 psi.800 psi. The outlet of the cylinder is to be linked to the high-pressure cell using a clean stainless steel tube.6.5 Analytical Balance, 0.1-mg sensitivity.6.6 Specimen Holders, degreased aluminu
37、m pans, 6.0 to 7.0-mm diameter.6.7 Core Hole Borer, cork borer or arch punch producing 6.3-mm 0.25-in. disks.7. Reagents and Materials7.1 All chemical reagents used in this test method shall be analytical grade unless otherwise specified.7.2 Hexane or Acetone, for cleaning specimen pans and stainles
38、s steel tubing, see 8.2 and 8.3.7.3 Indium (99.999 % Purity), for calibration purposes, see 9.1.7.4 Oxygen, purity 99.5 % for the test atmosphere.8. Precautions8.1 Oxygen is a strong oxidizer that vigorously accelerates combustion. Keep oil and grease away from equipment using orcontaining oxygen.8.
39、2 The stainless steel tube connecting the high-pressure cell to the oxygen cylinder must be thoroughly cleaned by hexane (oracetone) and then dried before being connected to the cell.8.3 All specimen holders should be cleaned by washing with hexane (or acetone) and then drying before being used in t
40、he test.8.3 The use of pressurized oxygen requires appropriate and careful handling procedures. The user of this test method shall befamiliar with the precautions described in Guide G88.9. Sampling9.1 Using a bore hole cutter, cork borer, or punch, cut several 6.3-mm 0.25-in. round specimen from the
41、 geosynthetic testsample.The test sample is compression molded into sheet format (thickness of 250 6 15 m) prior to analysis. Specimen disks(6.4-mm diameter) cut from the sheet will have a weight of approximately 5 to 10 mg, depending on sample density.NOTE 4If the sample requires homogenization pri
42、or to analysis, one of the procedures given in Appendix X1, Appendix X2, or Appendix X3 isrecommended. Poor sample uniformity will adversely affect test precision.NOTE 5If the sample contains a layer or layers of polymers other than polyolefins, the polyolefin may be tested separately from the entir
43、e crosssection. A recommended procedure is given in Appendix X4.9.2 Compression mold these assembled parts into a uniform plaque to a thickness of 0.25 mm 10 mil (see Practice D4703).NOTE 6The temperature at which molding takes place may be at or above the test temperature of this test method. Prolo
44、nged exposure to air at thesetemperatures may induce a negative bias into OIT measurement. Molding should be performed at as low a temperature and as quickly as possible tominimizedminimize this bias.9.3 Cut test specimens from the plaque using a 6.3-mm 0.25-in. bore hole cutter or punch.10. Calibra
45、tion10.1 Using Test Method E967, temperature calibrate the differential scanning calorimeter using indium metal and a heating rateof 1C/min1 Cmin from 145 to 165C.165 C.D5885/D5885M 17310.1.1 Perform the calibration step at least once a month or whenever changes have occurred in the experimental set
46、up.11. ProcedureNOTE 7Procedures for preparing the test specimen may be different for different polyolefin geosynthetic products, for example, geomembranes,geonets, geogrids, or geotextiles.11.1 Prepare a specimen with a mass of 5 6 1 mg.11.2 Place the weighed specimen into the cleaned specimen pan.
47、11.3 Place the specimen and reference pans into the cell.NOTE 8Open pans are used in this test method.11.4 Secure the top plate of the test chamber and tighten the cell system.11.5 Close the pressure release valve and the outlet valve. Open the inlet and pressurize the cell to 4.33.4 MPa 500 psi oxy
48、gen.Close the inlet valve.11.6 Commence programmed heating of the specimen from ambient temperature to 150C150 C at a rate of 20C/min.20 Cmin. Zero time is taken at the initiation of the temperature program. Hold the temperature isothermally at 150C150 Cuntil the oxidative exothermic peak is detecte
49、d. At the same time, the thermal curve of the entire test is being recorded. Other testtemperature may be used, with the agreement of all parties concerned, but must be reported.11.7 A slight gain in pressure at the beginning of the test is anticipated as the temperature of the cell increases. Decrease thepressure back to 3.4 MPa 500 psi by slightly opening the pressure release valve until the pressure comes down to 3.4 MPa.3.4 MPa. Alternatively, if the pressure increase with an instrument is known, pressurize
