1、Designation: D1693 12D1693 13Standard Test Method forEnvironmental Stress-Cracking of Ethylene Plastics1This standard is issued under the fixed designation D1693; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the determination of
3、 the susceptibility of ethylene plastics, as defined in Terminology D883, toenvironmental stress-cracking when subjected to the conditions herein specified. Under certain conditions of stress and in thepresence of environments such as soaps, wetting agents, oils, or detergents, ethylene plastics may
4、 exhibit mechanical failure bycracking.1.2 The values stated in SI units are to be regarded as 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
5、health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1There is no known ISO equivalent forto this standard.2. Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1204 Test Method for L
6、inear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated TemperatureD1248 Specification for Polyethylene Plastics Extrusion Materials for Wire and CableD3350 Specification for Polyethylene Plastics Pipe and Fittings MaterialsD4703 Practice for Compression Molding Thermoplasti
7、c Materials into Test Specimens, Plaques, or SheetsD4976 Specification for Polyethylene Plastics Molding and Extrusion MaterialsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ASTM Adjuncts:Apparatus Drawings and Blueprints33. Terminology3.1 Defin
8、itions:3.1.1 stress-crack, nan external or internal rupture in a plastic caused by tensile stresses less than its short-time mechanicalstrength.3.1.1.1 DiscussionThe development of such cracks is frequently accelerated by the environment to which the plastic is exposed. The stresses whichcause crack
9、ing may be present internally or externally, or may be a combination of these stresses. The appearance of a networkof fine cracks is called crazing.1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic
10、Materials.Current edition approved April 1, 2012April 1, 2013. Published May 2012April 2013. Originally approved in 1959. Last previous edition approved in 20082012 asD1693 - 08.D1693 - 12. DOI: 10.1520/D1693-12.10.1520/D1693-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or
11、 contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Detail drawings of the apparatus are available from ASTM Headquarters. Request ADJD169301,ADJD169302,ADJD169303, and ADJD169304.Th
12、is document 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 editi
13、ons as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
14、 United States13.1.2 stress-crack failure, nfor purposes of this test method, any crack visible to an observer with normal eyesight shall beinterpreted as a failure of the entire specimen (1).4 Extension of the controlled imperfection shall not be construed as a failure. Theappearance of more than o
15、ne crack in a single specimen shall be construed as a single failure.3.1.2.1 DiscussionCracks generally develop at the controlled imperfection and run to the outer edge of the specimen approximately at right anglesto it (2). The cracks need not extend completely through the specimen to constitute fa
16、ilure. Cracks sometimes develop under thepolymer surface, manifesting themselves as depressions on the surface. The time when this occurs should be noted, and if thedepression later develops into a crack, the time of dimpling should be considered as the failure time.4. Summary of Test Method4.1 Bent
17、 specimens of the plastic, each having a controlled imperfection on one surface, are exposed to the action of asurface-active agent. The proportion of the total number of specimens that crack in a given time is observed.5. Significance and Use5.1 This test method may be used for routine inspection p
18、urposes by subjecting a required number of specimens to the testconditions for a specified time and noting the number that fail. The cracking obtained with the test reagent is indicative of whatmay be expected from a wide variety of surface-active agents, soaps, and organic substances that are not a
19、bsorbed appreciably bythe polymer.5.2 Environmental stress-cracking is a property that is highly dependent upon the nature and level of the stresses applied andon the thermal history of the specimen (1). Under the conditions of the test method, high local multiaxial stresses are developedthrough the
20、 introduction of a controlled imperfection (2, 3). Environmental stress-cracking has been found to occur most readilyunder such conditions.NOTE 2Different types of polyethylene plastics as defined in Specification D1248 are generally tested under different levels of strain and stress. Whenit is expr
21、essly desired to compare the types at equal levels of strain, the specimens for all types should be tested under Condition B, Table 1 (4).5.3 Information from this test method is not intended to be used for direct application to engineering problems.NOTE 3Caution should be used in comparing and rank
22、ing various ethylene plastics into distinct and separate groups by this test method (see Section13 and Note 12).As thermal history is recognized as an important variable, test results by this test method employing laboratory molded samples cannot necessarily beexpected to show agreement with test re
23、sults from samples obtained by other means. The true performance potential of a given ethylene plastic may,however, best be determined with specimens obtained from commercially prepared items (5).6. Apparatus6.1 Blanking DieA rectangular die or other means suitable for cutting specimens 38 6 2.5 mm
24、by 13 6 0.8 mm (1.5 6 0.1in. by 0.50 6 0.03 in.). These specimens must be cut with square edges. Beveled ends in particular are to be avoided.4 The boldface numbers in parentheses refer to the list of references at the end of this test method.TABLE 1 Standard Test ConditionsConditionSpecimenThicknes
25、s Notch Depth Bath Temperature,CmmA in. mmA in.AB min 3.00 0.120 0.50 0.020 50max 3.30 0.130 0.65 0.025BB min 1.84 0.0725 0.30 0.012 50max 1.97 0.0775 0.40 0.015CC min 1.84 0.0725 0.30 0.012 100Cmax 1.97 0.0775 0.40 0.015A Dimensional values are not exactly equivalent. However, for referee purposest
26、he metric units shall apply.B For referee purposes, concentration of Igepal will be consistent with theappropriate material standard. If no concentration is given, then 10 % volumesolution shall be used.C At a temperature of 100C, a full-strength reagent, rather than an aqueoussolution of a reagent,
27、 is generally used because solutions tend to change theircompositions by water evaporation losses during the period of test.D1693 1326.2 JigAjig for making a controlled imperfection in specimens of the dimensions shown in Table 1, parallel to the long edgesof the specimen and centered on one of the
28、broad faces. TheA jig as shown in Fig. 1 and capable of notching the specimens inaccordance with 10.2 shall be used.NOTE 4It is recommended that the jig be permanently mounted to ensure notching consistency.6.3 Specimen HoldersLengths of hard or half-hard brass channel having the dimensions shown in
29、 (B) of Fig. 2 shall be used.The sides of the channel shall be parallel and the inside corners sharp and square. Any burrs present on the inside of the channelshall be removed. The inside width is critical (see Dimension F in Fig. 2).6.4 Test Tubes and ClosuresHard glass tubes nominally 200 mm long
30、with a preferred minimum inside diameter of 31.5 mmand a cork or rubber stopper. Alternatively, tubes with threaded ends and plastic caps are permissible.NOTE 5Some older test tubes have inside diameters of less than 31.5 mm. These are acceptable as long as there is adequate clearance to allow thefi
31、lled specimen holder to be inserted into the tube without any interference.NOTE 6Hard glass (borosilicate) tubes and No. 15 corks have been found satisfactory.6.5 Aluminum FoilApproximately 0.08 to 0.13 mm (0.003 to 0.005 in.) thick, for wrapping.6.6 Constant-Temperature BathA constant-temperature l
32、iquid bath maintained at 50.0 6 0.5C for Conditions A and B ofTable 1 and 100.0 6 0.5C for Condition C of Table 1.6.7 Test Tube RackA rack to hold test tubes immersed to reagent level.6.8 Bending ClampAs shown in Fig. 3.6.9 Transfer ToolAs shown in Fig. 4.7. Reagent7.1 The preferred reagent is a non
33、ylphenoxy poly(ethyleneoxy)ethanol.5NOTE 7There are environmental concerns regarding the disposal of Nonylphenoxy poly(ethyleneoxy) ethanol (CAS 68412-54-4), for example, IgepalCO-630. Users are advised to consult their supplier or local environmental office and follow the guidelines provided for th
34、e proper disposal of thischemical.NOTE 8The reagent should be stored in closed metal or glass containers because it is somewhat hygroscopic.NOTE 9The manufacturer has stated that this aggressive agent undergoes no known degradation when used as follows: A10 % volume solution inwater at 50C for 1000
35、h of testing.NOTE 10The appearance of carbonyl bands in an Igepal Fourier transform infrared (FT-IR) scan is an indication of degradation.7.2 Other surface-active agents, soaps, or any liquid organic substance that is not absorbed appreciably by the polymer can alsobe used.5 For referee purposes Ige
36、pal CO-630 should be obtained from Rhone-Poulenc, Prospect Plains, Cranbury, NJ 08512.mm in.A 3 18B 18.919.2 0.7450.755C (radius) 1.5 max 116 maxFIG. 1 Nicking JigD1693 1338. Test Specimen8.1 Unless otherwise specified, the test specimens shall be molded in accordance with Procedure C of Annex A1 of
37、 PracticeD4703.NOTE 11Use no liquid release agents, waxes, polishes, and so forth, when molding. However, inert materials such as polyester film, unplasticizedcellophane, polytetrafluoroethylene, and aluminum foil have been found satisfactory.8.2 Sheets may be examined for internal stresses by takin
38、g specimens from random locations in the sheet and placing them ina Petri dish containing 3 mm (18 in.) of talc and setting the dish in an air oven at 130C for Types I and II polyethylene plasticand at 150C for Types III and IV polyethylene plastic for 30 minutes. If shrinkage of the specimens is le
39、ss than 10 % in thelengthwise direction, the molded sheet can be considered satisfactory (see also Test Method D1204).8.3 Cut specimens from smooth sheet pressed from granules or mill-massed material to the dimensions given in Fig. 2 (A). Usea die or other device that produces specimens with clean-c
40、ut, square, unbeveled edges. The specimens should be cut within 24 hafter the sheets are prepared.Dimensionsmm in.A 38 2.5 1.5 0.1B 13 0.8 0.5 0.03C see Table 1D see Table 1E 165 6 12F(outside) 16 58(inside) 11.75 0.05 0.463 0.002G 10 38H 15 3764I 2 0.081 (12 B polyethylene; stress-crackingANNEX(Man
41、datory Information)A1. GRAPHICAL METHOD OF DETERMINING FAILURE POINTSA1.1 Under some circumstances a 50 % failure point (F50) is of interest and relevant, as other failure points may be. An exampleof calculation using a graphical method for the 50 % (or almost any other %) failure point is as follow
42、s:A1.1.1 The value reported by this graphical method is obtained without reference to 0 % failure time. Plot the data on logarithmicprobability graph paper, Fig.A1.1 or Fig.A1.2, with appropriate time scales chosen and probability expressed as percentage. (Theuser is encouraged to copy these figures
43、.) Elapsed time belongs on the logarithmic scale. Number of failures (breaks or cracks),divided by one more than the number of original specimens, belongs on the probability scale. Adding one to the number ofspecimens provides a divisor that (a) produces a symmetrical treatment of the data, (b) enab
44、les plotting all the data points, (c) iseasy to remember without a table, (d) permits using any otherwise appropriate number of specimens, and (e) is widely accepted.NOTE A1.1This plotting convention does not necessarily provide a mathematically optimum unbiased estimate of the standard deviation, b
45、ut using theconvention appears nearly optimal with ten specimens. Considerable mathematical bias is usually introduced anyway by the economic necessity ofperiodic inspection, that is, not continuously watching for breaks during 48 h. The recorded failure times are generally later than the actual fai
46、lure times.This limitation seems to engulf the slight bias introduced for convenience by the plotting convention (6), (7). For further information see Refs (6-9) andthe references contained therein.A1.2 If one or more specimens broke since the previous observation, plot a point for each of the faile
47、d specimens. Therefore, onepoint will appear for each specimen that fails. A point does not necessarily appear for each observation time. Draw the best-fittingstraight line for the plot.The time indicated at the intersection of the data line and the 50 % probability line shall be the 50 % failurepoi
48、nt (F50). Similarly, F10, F20, F90, or Fx information is obtained from the intersection of the data line and the 10 %, 20 %, 90 %,or X % probability lines. The F0 and F100 points cannot be obtained, as they do not formally exist.A1.3 A specimen that breaks on bending is called failed at 1 min, or le
49、ss, an arbitrary convenient short time that is less than thefirst inspection time. The plotting directions are then still valid. Convenient suitable inspection times have been found to be 0.1,0.25, 0.5, 1.0, 1.5, 2, 3, 4, 5, 8, 16, 24, 32, 40, and 48 h. Extended tests are inspected every 24 h thereafter. Certain work scheduleswould eliminate the 16 and 32-h inspections, and possibly shorten the 8, 24, and 48-h periods a few minutes to enable inspectionduring an 8-h working day. Laboratories on round-the-clock operations would no
