ASTM D1693-21

Standard Test Method for Environmental Stress-Cracking of Ethylene Plastics

SIGNIFICANCE AND USE
5.1 This test method may be used for routine inspection purposes by subjecting a required number of specimens to the test conditions for a specified time and noting the number that fail. The cracking obtained with the test reagent is indicative of what may be expected from a wide variety of surface-active agents, soaps, and organic substances that are not absorbed appreciably by the polymer.  
5.2 Environmental stress-cracking is a property that is highly dependent upon the nature and level of the stresses applied and on the thermal history of the specimen (1). Under the conditions of the test method, high local multiaxial stresses are developed through the introduction of a controlled imperfection (2, 3). Environmental stress-cracking has been found to occur most readily under such conditions.  
Note 2: Different types of polyethylene plastics as defined in Specification D1248 are generally tested under different levels of strain and stress. When it is expressly desired to compare the types at equal levels of strain, the specimens for all types should be tested under Condition B, Table 1 (4) .  (A) Dimensional values are not exactly equivalent. However, for referee purposes the metric units shall apply.(B) For referee purposes, concentration of Igepal will be consistent with the appropriate material standard. If no concentration is given, then 10 % volume solution shall be used.(C) At a temperature of 100°C, a full-strength reagent, rather than an aqueous solution of a reagent, is generally used because solutions tend to change their compositions by water evaporation losses during the period of test.
5.3 Information from this test method is not intended to be used for direct application to engineering problems.  
Note 3: Caution should be used in comparing and ranking various ethylene plastics into distinct and separate groups by this test method (see Section 13 and Note 12).
As thermal history is recognized as an important variable, test results by this...
SCOPE
1.1 This test method covers the determination of the susceptibility of ethylene plastics, as defined in Terminology D883, to environmental stress-cracking when subjected to the conditions herein specified. Under certain conditions of stress and in the presence of environments such as soaps, wetting agents, oils, or detergents, ethylene plastics may exhibit mechanical failure by cracking.  
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 responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: There is no known ISO equivalent to this standard.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2021
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.15 - Thermoplastic Materials

Relations

• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM D1204-14(2020) - Standard Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated Temperature
• Effective Date: 01-Apr-2020
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D883-19c - Standard Terminology Relating to Plastics
• Effective Date: 01-Aug-2019
• Refers: ASTM D883-19a - Standard Terminology Relating to Plastics
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2019
• Refers: ASTM D883-18a - Standard Terminology Relating to Plastics
• Effective Date: 01-Dec-2018
• Refers: ASTM D883-18 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2018
• Refers: ASTM D883-17 - Standard Terminology Relating to Plastics
• Effective Date: 15-Aug-2017
• Refers: ASTM D1248-16 - Standard Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
• Effective Date: 15-Nov-2016
• Refers: ASTM D1204-14 - Standard Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated Temperature
• Effective Date: 01-Mar-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM D883-12e1 - Standard Terminology Relating to Plastics
• Effective Date: 15-Nov-2012
• Refers: ASTM D1248-12 - Standard Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
• Effective Date: 01-Apr-2012

Overview

ASTM D1693-21 is the internationally recognized standard test method for evaluating the environmental stress-cracking of ethylene plastics. Developed by ASTM International, this standard allows users to determine the susceptibility of ethylene plastics, a material commonly encountered as various types of polyethylene, to failure when exposed to surface-active agents such as soaps, detergents, and oils under specified stress conditions. While widely used in materials testing, the results are not intended for direct application in engineering design but serve as a quality and performance benchmark for manufacturers, researchers, and quality control laboratories.

Key Topics

• Purpose of the Test: This method assesses the propensity of ethylene plastics to crack in the presence of chemical agents under stress, simulating real-world exposure to substances like detergents or wetting agents.
• Test Procedure: Specimens of a specified size are notched to introduce a controlled imperfection, bent to induce stress, and then immersed in a stress-cracking reagent at a controlled temperature. Failures (cracks) are monitored over a defined period.
• Variables Considered: The standard recognizes that environmental stress-cracking is affected by:
  • The type and concentration of the chemical agent (most commonly a solution like Igepal CO-630).
  • The thermal history and crystallinity of the specimen.
  • The magnitude and nature of applied stresses.
  • The physical dimensions and notch depth of specimens.
• Data Reporting: Results include identification of the plastic material, preparation details, test conditions, reagent specifics, and the percentage or time to failure, allowing for material comparisons and batch quality monitoring.

Applications

ASTM D1693-21 is critical in several industries and scenarios where environmental stress-cracking can compromise polyethylene component integrity:

• Material Selection and QC: Manufacturers of polyethylene products, such as containers, piping, or packaging, use this test for routine lot inspection and quality control to verify expected resistance to cracking.
• Comparative Testing: The method enables comparative evaluation of different types or grades of ethylene plastics, providing insight into material performance in aggressive environments.
• R&D and Material Development: Researchers employ this standard during the development and formulation of new polyethylene materials or additives to enhance environmental stress-cracking resistance.
• Performance Benchmarking: Certifying compliance with this standard can support customer requirements, distinguish material grades, and underpin technical datasheets.

It is important to note that while this method is indicative of a material's performance in the presence of certain surface-active agents, it may not encompass all service conditions encountered in real-world use, and caution should be exercised in extrapolating data for design purposes.

Related Standards

Several other ASTM standards are referenced within ASTM D1693-21, supporting specimen preparation, terminology, and polyethylene classification:

• ASTM D618 - Conditioning Plastics for Testing
• ASTM D883 - Terminology Relating to Plastics
• ASTM D1248 - Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
• ASTM D3350 - Specification for Polyethylene Plastics Pipe and Fittings Materials
• ASTM D4703 - Compression Molding Thermoplastic Materials into Test Specimens
• ASTM D4976 - Specification for Polyethylene Plastics Molding and Extrusion Materials
• ASTM E691 - Conducting an Interlaboratory Study to Determine the Precision of a Test Method

Note: ASTM D1693-21 currently has no ISO equivalent, marking it as a unique benchmark for environmental stress-cracking resistance testing of ethylene plastics.

---

Keywords: ASTM D1693-21, environmental stress-cracking, polyethylene, ethylene plastics, surface-active agents, material testing, quality control, plastics standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D1693 − 21
Standard Test Method for
Environmental Stress-Cracking of Ethylene Plastics
This standard is issued under the fixed designation D1693; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* D3350 Specification for Polyethylene Plastics Pipe and Fit-
tings Materials
1.1 This test method covers the determination of the sus-
D4703 Practice for Compression Molding Thermoplastic
ceptibility of ethylene plastics, as defined in Terminology
Materials into Test Specimens, Plaques, or Sheets
D883, to environmental stress-cracking when subjected to the
D4976 Specification for Polyethylene Plastics Molding and
conditions herein specified. Under certain conditions of stress
Extrusion Materials
and in the presence of environments such as soaps, wetting
E691 Practice for Conducting an Interlaboratory Study to
agents, oils, or detergents, ethylene plastics may exhibit
Determine the Precision of a Test Method
mechanical failure by cracking.
2.2 ASTM Adjuncts:
1.2 The values stated in SI units are to be regarded as 3
Apparatus Drawings and Blueprints
standard.
3. Terminology
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 stress-crack, n—an external or internal rupture in a
priate safety, health, and environmental practices and deter-
plastic caused by tensile stresses less than its short-time
mine the applicability of regulatory limitations prior to use.
mechanical strength.
3.1.1.1 Discussion—The development of such cracks is
NOTE 1—There is no known ISO equivalent to this standard.
frequently accelerated by the environment to which the plastic
1.4 This international standard was developed in accor-
is exposed. The stresses which cause cracking may be present
dance with internationally recognized principles on standard-
internally or externally, or may be a combination of these
ization established in the Decision on Principles for the
stresses. The appearance of a network of fine cracks is called
Development of International Standards, Guides and Recom-
crazing.
mendations issued by the World Trade Organization Technical
3.1.2 stress-crack failure, n—for purposes of this test
Barriers to Trade (TBT) Committee.
method, any crack visible to an observer with normal eyesight
2. Referenced Documents
shall be interpreted as a failure of the entire specimen (1).
Extension of the controlled imperfection shall not be construed
2.1 ASTM Standards:
as a failure. The appearance of more than one crack in a single
D618 Practice for Conditioning Plastics for Testing
specimen shall be construed as a single failure.
D883 Terminology Relating to Plastics
3.1.2.1 Discussion—Cracks generally develop at the con-
D1204 Test Method for Linear Dimensional Changes of
trolled imperfection and run to the outer edge of the specimen
Nonrigid Thermoplastic Sheeting or Film at Elevated
approximately at right angles to it (2). The cracks need not
Temperature
extend completely through the specimen to constitute failure.
D1248 Specification for Polyethylene Plastics Extrusion
Cracks sometimes develop under the polymer surface, mani-
Materials for Wire and Cable
festing themselves as depressions on the surface. The time
when this occurs should be noted, and if the depression later
This test method is under the jurisdiction ofASTM Committee D20 on Plastics
develops into a crack, the time of dimpling should be consid-
and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materi-
ered as the failure time.
als.
Current edition approved Oct. 1, 2021. Published October 2021. Originally
ɛ1
approved in 1959. Last previous edition approved in 2015 as D1693 - 15 . DOI:
10.1520/D1693-21. Detailed drawings of the apparatus are available from ASTM Headquarters.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Request ADJD169302, ADJD169303,or ADJD169304. For a complete set of all
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM drawings, request ADJD1693CS.
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the list of references at the end of
the ASTM website. this test method.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1693 − 21
TABLE 1 Standard Test Conditions
Specimen
Notch Depth
Bath Temperature,
Thickness
Condition
°C
A A
mm in. mm in.
B
A min 3.00 0.120 0.50 0.020 50
max 3.30 0.130 0.65 0.025
B
B min 1.84 0.0725 0.30 0.012 50
max 1.97 0.0775 0.40 0.015
C C
C min 1.84 0.0725 0.30 0.012 100
max 1.97 0.0775 0.40 0.015
A
Dimensional values are not exactly equivalent. However, for referee purposes the
metric units shall apply.
B
For referee purposes, concentration of Igepal will be consistent with the appro-
priate material standard. If no concentration is given, then 10 % volume solution
shall be used.
C
At a temperature of 100°C, a full-strength reagent, rather than an aqueous
solution of a reagent, is generally used because solutions tend to change their
compositions by water evaporation losses during the period of test.
mm in.
A3 ⁄8
4. Summary of Test Method
B 18.9–19.2 0.745–0.755
C (radius) 1.5 max ⁄16 max
4.1 Bent specimens of the plastic, each having a controlled
imperfection on one surface, are exposed to the action of a
surface-active agent. The proportion of the total number of
FIG. 1 Nicking Jig
specimens that crack in a given time is observed.
5. Significance and Use
(1.5 6 0.1 in. by 0.50 6 0.03 in.). These specimens must be
cut with square edges. Beveled ends in particular are to be
5.1 This test method may be used for routine inspection
avoided.
purposes by subjecting a required number of specimens to the
test conditions for a specified time and noting the number that
6.2 Jig—A jig for making a controlled imperfection in
fail.The cracking obtained with the test reagent is indicative of
specimens of the dimensions shown in Table 1, parallel to the
what may be expected from a wide variety of surface-active
long edges of the specimen and centered on one of the broad
agents, soaps, and organic substances that are not absorbed
faces. A jig as shown in Fig. 1 and capable of notching the
appreciably by the polymer.
specimens in accordance with 10.2 shall be used.
5.2 Environmental stress-cracking is a property that is
NOTE 4—It is recommended that the jig be permanently mounted to
highly dependent upon the nature and level of the stresses ensure notching consistency.
applied and on the thermal history of the specimen (1). Under
6.3 Specimen Holders—Lengths of hard or half-hard brass
the conditions of the test method, high local multiaxial stresses
or stainless steel channel having the dimensions shown in (B)
are developed through the introduction of a controlled imper-
of Fig. 2 shall be used. The sides of the channel shall be
fection (2, 3). Environmental stress-cracking has been found to
parallel and the inside corners sharp and square. Any burrs
occur most readily under such conditions.
present on the inside of the channel shall be removed. The
inside width is critical (see Dimension F in Fig. 2).
NOTE 2—Different types of polyethylene plastics as defined in Speci-
fication D1248 are generally tested under different levels of strain and
6.4 Test Tubes and Closures—Hard glass tubes nominally
stress.When it is expressly desired to compare the types at equal levels of
200 mm long with a preferred minimum inside diameter of
strain, the specimens for all types should be tested under Condition B,
31.5mmandacorkorrubberstopper.Alternatively,tubeswith
Table 1 (4).
threaded ends and plastic caps are permissible.
5.3 Information from this test method is not intended to be
used for direct application to engineering problems.
NOTE 5—Some older test tubes have inside diameters of less than 31.5
mm. These are acceptable as long as there is adequate clearance to allow
NOTE 3—Caution should be used in comparing and ranking various
the filled specimen holder to be inserted into the tube without any
ethylene plastics into distinct and separate groups by this test method (see
interference.
Section 13 and Note 12).
NOTE 6—Hard glass (borosilicate) tubes and No. 15 corks have been
As thermal history is recognized as an important variable, test results by
found satisfactory.
this test method employing laboratory molded samples cannot necessarily
6.5 Aluminum Foil—Approximately0.08to0.13mm(0.003
be expected to show agreement with test results from samples obtained by
other means. The true performance potential of a given ethylene plastic
to 0.005 in.) thick, for wrapping.
may, however, best be determined with specimens obtained from com-
6.6 Constant-Temperature Bath—A constant-temperature
mercially prepared items (5).
liquid bath maintained at 50.0 6 0.5°C for ConditionsAand B
6. Apparatus of Table 1 and 100.0 6 0.5°C for Condition C of Table 1.
6.1 Blanking Die—Arectangulardieorothermeanssuitable 6.7 Test Tube Rack—A rack to hold test tubes immersed to
for cutting specimens 38 6 2.5 mm by 13 6 0.8 mm reagent level.
D1693 − 21
Dimensions
mm in.
A 38±2.5 1.5±0.1
B 13±0.8 0.5±0.03
C see Table 1
D see Table 1
E 165 6 ⁄2
F
(outside) 16 ⁄8
(inside) 11.75 ± 0.05 0.463 ± 0.002
G10 ⁄8
H15 ⁄64
I 2 0.081 (12B&S)
3 19
J ten 5-mm holes ten ⁄16-in. holes, ⁄32-in.
15-mm centers centers
FIG. 2 Test Equipment
NOTE 9—The manufacturer has stated that this aggressive agent
6.8 Bending Clamp—As shown in Fig. 3.
undergoes no known degradation when used as follows: A10 % volume
6.9 Transfer Tool—As shown in Fig. 4.
solution in water at 50°C for 1000 h of testing.
NOTE 10—The appearance of carbonyl bands in an Igepal Fourier
7. Reagent
transform infrared (FT-IR) scan is an indication of degradation.
7.1 The preferred reagent is a nonylphenoxy poly(ethylene- 7.2 Other surface-active agents, soaps, or any liquid organic
oxy)ethanol. substance that is not absorbed appreciably by the polymer can
also be used.
NOTE 7—There are environmental concerns regarding the disposal of
Nonylphenoxy poly(ethyleneoxy) ethanol (CAS 68412-54-4), for
8. Test Specimen
example, Igepal CO-630. Users are advised to consult their supplier or
8.1 Unless otherwise specified, the test specimens shall be
local environmental office and follow the guidelines provided for the
proper disposal of this chemical. molded in accordance with Procedure C of Annex A1 of
NOTE 8—The reagent should be stored in closed metal or glass
Practice D4703.
containers because it is somewhat hygroscopic.
NOTE 11—Use no liquid release agents, waxes, polishes, and so forth,
when molding. However, inert materials such as polyester film, unplasti-
For referee purposes Igepal CO-630 should be obtained from Rhone-Poulenc, cized cellophane, polytetrafluoroethylene, and aluminum foil have been
Prospect Plains, Cranbury, NJ 08512. found satisfactory.
D1693 − 21
FIG. 3 Bending Clamp Assembly
NOTE 1—X = 10.5 6 0.5 mm (0.41 6 0.02 in.)
FIG. 4 Transfer Tool Assembly
0.910 and 0.925 are tested under Condition A. Polyethylenes with
8.2 Sheets may be examined for internal stresses by taking
densities >0.925 are tested under Condition B. Condition C may be used
specimensfromrandomlocationsinthesheetandplacingthem
to accelerate testing for materials with extremely high ESCR values. The
in a Petri dish containing 3 mm ( ⁄8 in.) of talc and setting the
user of this test method should refer to the material specifications such as
dish in an air oven at 130°C for Types I and II polyethylene
D1248, D3350,or D4976 for specific test conditions.
plastic and at 150°C for Types III and IV polyethylene plastic
10.2 Give each conditioned specimen a controlled imper-
for 30 minutes. If shrinkage of the specimens is less than 10 %
fection (notch) on one surface as shown in (A)of Fig. 2. Use
inthelengthwisedirection,themoldedsheetcanbeconsidered
satisfactory (see also Test Method D1204). a sharp blade, mounted in the jig shown in Fig. 1, for making
this imperfection.Adepth micrometer may be used for setting
8.3 Cutspecimensfromsmoothsheetpressedfromgranules
the blade in the jig so that the notch depth is controlled as
or mill-massed material to the dimensions given in Fig. 2 (A).
specified in Table 1. The difference between the height at the
Use a die or other device that produces specimens with
top of the blade edge and the channel of the jig where the top
clean-cut, square, unbeveled edges. The specimens should be
of the specimen rests when being nicked is measured to ensure
cut within 24 h after the sheets are prepared.
the proper setting of the blade.
9. Conditioning
NOTE 13—Where it is desired to nick specimens to a notch depth
9.1 Unless otherwise specified, the test specimens should be
required by Conditions B and C in Table 1 and the available jig has been
conditioned in accordance with ProcedureAof Practice D618.
designed for nicking specimens to a notch depth required by ConditionA
Do not bend the test specimens, nick, or treat them with the
in Table 1, brass shim stock 0.21 mm (0.008 in.) thick may be used to
reagent until immediately prior to the test. Testing should be
make the more shallow notch. Brass shim stock is cut wide enough so that
started a minimum of 40 h and a maximum of 96 h after
it fits snugly inside the jig channel where the specimen rests when nicked.
The length of the shim should be such that it extends over the blade,
conditioning the specimens has begun.
around the end of the jig, and under the end so that the jig will rest on
10. Procedure
about1or2in.oftheshimstock.Theweightofthejigrestingontheshim
stockpreventsdeformationoftheshimstockduringthenickingoperation.
10.1 Select the condition desired from Table 1.
An oblong hole long enough to fit completely over the protruding blade is
NOTE 12—Generally, polyethylene plastics with densities between cut in the other end of the shim stock. Discard shim stock that becomes
D1693 − 21
wrinkledordeformedinsuchawayastopreventthespecimenfromlying TABLE 2 ESCR of Polyethylene, F in Hours
horizontal in the jig.
Ave.
Sample S S rR S /X S /X
r R r R
NOTE 14—In order to maintain notch consistency, it is recommended to F ,h
keep the force applied to the jig handle constant. This can be done by
Resin A, molded plaques 49.6 3.7 19.1 10.5 54.1 7.5 % 39 %
applying the force at the same location of the jig handle each time using
0.945/0.3 extruded sheets 52.7 2.3 28.8 6.5 81.5 4.4 % 55 %
a torque wrench.
Resin B, molded plaques 42.0 3.4 14.2 9.6 40.2 8.1 % 34 %
0.950/0.06 extruded sheets 49.1 8.0 14.2 22.6 40.2 16 % 29 %
NOTE 15—The notch depth correlates with the depth of blade setting,
which is measured by a depth micrometer (see 10.2). The notch depth can
be verified by micr
...

This 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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D1693 − 15 D1693 − 21
Standard Test Method for
Environmental Stress-Cracking of Ethylene Plastics
This standard is issued under the fixed designation D1693; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Adjunct footnote was editorially corrected in August 2020.
1. Scope*
1.1 This test method covers the determination of the susceptibility of ethylene plastics, as defined in Terminology D883, to
environmental stress-cracking when subjected to the conditions herein specified. Under certain conditions of stress and in the
presence of environments such as soaps, wetting agents, oils, or detergents, ethylene plastics may exhibit mechanical failure by
cracking.
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 responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
NOTE 1—There is no known ISO equivalent to this standard.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D618 Practice for Conditioning Plastics for Testing
D883 Terminology Relating to Plastics
D1204 Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or Film at Elevated Temperature
D1248 Specification for Polyethylene Plastics Extrusion Materials for Wire and Cable
D3350 Specification for Polyethylene Plastics Pipe and Fittings Materials
D4703 Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets
D4976 Specification for Polyethylene Plastics Molding and Extrusion Materials
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.
Current edition approved May 1, 2015Oct. 1, 2021. Published June 2015October 2021. Originally approved in 1959. Last previous edition approved in 20132015 as
ɛ1
D1693 - 13.D1693 - 15 . DOI: 10.1520/D1693-15E01.10.1520/D1693-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1693 − 21
2.2 ASTM Adjuncts:
Apparatus Drawings and Blueprints
3. Terminology
3.1 Definitions:
3.1.1 stress-crack, n—an external or internal rupture in a plastic caused by tensile stresses less than its short-time mechanical
strength.
3.1.1.1 Discussion—
The development of such cracks is frequently accelerated by the environment to which the plastic is exposed. The stresses which
cause cracking may be present internally or externally, or may be a combination of these stresses. The appearance of a network
of fine cracks is called crazing.
3.1.2 stress-crack failure, n—for purposes of this test method, any crack visible to an observer with normal eyesight shall be
interpreted as a failure of the entire specimen (1). Extension of the controlled imperfection shall not be construed as a failure. The
appearance of more than one crack in a single specimen shall be construed as a single failure.
3.1.2.1 Discussion—
Cracks generally develop at the controlled imperfection and run to the outer edge of the specimen approximately at right angles
to it (2). The cracks need not extend completely through the specimen to constitute failure. Cracks sometimes develop under the
polymer surface, manifesting themselves as depressions on the surface. The time when this occurs should be noted, and if the
depression later develops into a crack, the time of dimpling should be considered as the failure time.
4. Summary of Test Method
4.1 Bent specimens of the plastic, each having a controlled imperfection on one surface, are exposed to the action of a
surface-active agent. The proportion of the total number of specimens that crack in a given time is observed.
5. Significance and Use
5.1 This test method may be used for routine inspection purposes by subjecting a required number of specimens to the test
conditions for a specified time and noting the number that fail. The cracking obtained with the test reagent is indicative of what
may be expected from a wide variety of surface-active agents, soaps, and organic substances that are not absorbed appreciably by
the polymer.
5.2 Environmental stress-cracking is a property that is highly dependent upon the nature and level of the stresses applied and on
the thermal history of the specimen (1). Under the conditions of the test method, high local multiaxial stresses are developed
through the introduction of a controlled imperfection (2, 3). Environmental stress-cracking has been found to occur most readily
under such conditions.
NOTE 2—Different types of polyethylene plastics as defined in Specification D1248 are generally tested under different levels of strain and stress. When
it is expressly 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 3—Caution should be used in comparing and ranking various ethylene plastics into distinct and separate groups by this test method (see Section
13 and Note 12).
As thermal history is recognized as an important variable, test results by this test method employing laboratory molded samples cannot necessarily be
expected to show agreement with test results 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. Apparatus
6.1 Blanking Die—A rectangular die or other means suitable for cutting specimens 38 6 2.5 mm by 13 6 0.8 mm (1.5 6 0.1 in.
by 0.50 6 0.03 in.). These specimens must be cut with square edges. Beveled ends in particular are to be avoided.
Detailed drawings of the apparatus are available from ASTM Headquarters. Request ADJD169302, ADJD169303, or ADJD169304. For a complete set of all drawings,
request ADJD1693CS.
The boldface numbers in parentheses refer to the list of references at the end of this test method.
D1693 − 21
TABLE 1 Standard Test Conditions
Specimen
Notch Depth
Bath Temperature,
Thickness
Condition
°C
A A
mm in. mm in.
B
A min 3.00 0.120 0.50 0.020 50
max 3.30 0.130 0.65 0.025
B
B min 1.84 0.0725 0.30 0.012 50
max 1.97 0.0775 0.40 0.015
C C
C min 1.84 0.0725 0.30 0.012 100
max 1.97 0.0775 0.40 0.015
A
Dimensional values are not exactly equivalent. However, for referee purposes the
metric units shall apply.
B
For referee purposes, concentration of Igepal will be consistent with the appro-
priate material standard. If no concentration is given, then 10 % volume solution
shall be used.
C
At a temperature of 100°C, a full-strength reagent, rather than an aqueous
solution of a reagent, is generally used because solutions tend to change their
compositions by water evaporation losses during the period of test.
6.2 Jig—A jig for making a controlled imperfection in specimens of the dimensions shown in Table 1, parallel to the long edges
of the specimen and centered on one of the broad faces. A jig as shown in Fig. 1 and capable of notching the specimens in
accordance with 10.2 shall be used.
NOTE 4—It is recommended that the jig be permanently mounted to ensure notching consistency.
6.3 Specimen Holders—Lengths of hard or half-hard brass or stainless steel channel having the dimensions shown in (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 channel shall be removed. The inside width is critical (see Dimension F in Fig. 2).
6.4 Test Tubes and Closures—Hard glass tubes nominally 200 mm long with a preferred minimum inside diameter of 31.5 mm
and a cork or rubber stopper. Alternatively, tubes with threaded ends and plastic caps are permissible.
NOTE 5—Some older test tubes have inside diameters of less than 31.5 mm. These are acceptable as long as there is adequate clearance to allow the filled
specimen holder to be inserted into the tube without any interference.
NOTE 6—Hard glass (borosilicate) tubes and No. 15 corks have been found satisfactory.
6.5 Aluminum Foil—Approximately 0.08 to 0.13 mm (0.003 to 0.005 in.) thick, for wrapping.
6.6 Constant-Temperature Bath—A constant-temperature liquid bath maintained at 50.0 6 0.5°C for Conditions A and B of Table
1 and 100.0 6 0.5°C for Condition C of Table 1.
6.7 Test Tube Rack—A rack to hold test tubes immersed to reagent level.
6.8 Bending Clamp—As shown in Fig. 3.
6.9 Transfer Tool—As shown in Fig. 4.
7. Reagent
7.1 The preferred reagent is a nonylphenoxy poly(ethyleneoxy)ethanol.
NOTE 7—There are environmental concerns regarding the disposal of Nonylphenoxy poly(ethyleneoxy) ethanol (CAS 68412-54-4), for example, Igepal
CO-630. Users are advised to consult their supplier or local environmental office and follow the guidelines provided for the proper disposal of this
chemical.
For referee purposes Igepal CO-630 should be obtained from Rhone-Poulenc, Prospect Plains, Cranbury, NJ 08512.
D1693 − 21
mm in.
A 3 ⁄8
B 18.9–19.2 0.745–0.755
C (radius) 1.5 max ⁄16 max
FIG. 1 Nicking Jig
NOTE 8—The reagent should be stored in closed metal or glass containers because it is somewhat hygroscopic.
NOTE 9—The manufacturer has stated that this aggressive agent undergoes no known degradation when used as follows: A10 % volume solution in water
at 50°C for 1000 h of testing.
NOTE 10—The 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 also
be used.
8. Test Specimen
8.1 Unless otherwise specified, the test specimens shall be molded in accordance with Procedure C of Annex A1 of Practice
D4703.
NOTE 11—Use no liquid release agents, waxes, polishes, and so forth, when molding. However, inert materials such as polyester film, unplasticized
cellophane, polytetrafluoroethylene, and aluminum foil have been found satisfactory.
8.2 Sheets may be examined for internal stresses by taking specimens from random locations in the sheet and placing them in a
Petri dish containing 3 mm ( ⁄8 in.) of talc and setting the dish in an air oven at 130°C for Types I and II polyethylene plastic and
at 150°C for Types III and IV polyethylene plastic for 30 minutes. If shrinkage of the specimens is less than 10 % in the lengthwise
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). Use
a die or other device that produces specimens with clean-cut, square, unbeveled edges. The specimens should be cut within 24 h
after the sheets are prepared.
9. Conditioning
9.1 Unless otherwise specified, the test specimens should be conditioned in accordance with Procedure A of Practice D618. Do
not bend the test specimens, nick, or treat them with the reagent until immediately prior to the test. Testing should be started a
minimum of 40 h and a maximum of 96 h after conditioning the specimens has begun.
D1693 − 21
Dimensions
mm in.
A 38 ± 2.5 1.5 ± 0.1
B 13 ± 0.8 0.5 ± 0.03
C see Table 1
D see Table 1
E 165 6 ⁄2
F
(outside) 16 ⁄8
(inside) 11.75 ± 0.05 0.463 ± 0.002
G 10 ⁄8
H 15 ⁄64
I 2 0.081 (12 B & S)
3 19
J ten 5-mm holes ten ⁄16-in. holes, ⁄32-in.
15-mm centers centers
FIG. 2 Test Equipment
10. Procedure
10.1 Select the condition desired from Table 1.
NOTE 12—Generally, polyethylene plastics with densities between 0.910 and 0.925 are tested under Condition A. Polyethylenes with densities >0.925 are
tested under Condition B. Condition C may be used to accelerate testing for materials with extremely high ESCR values. The user of this test method
should refer to the material specifications such as D1248, D3350, or D4976 for specific test conditions.
10.2 Give each conditioned specimen a controlled imperfection (notch) on one surface as shown in (A) of Fig. 2. Use a sharp
blade, mounted in the jig shown in Fig. 1, for making this imperfection. A depth micrometer may be used for setting the blade in
the jig so that the notch depth is controlled as specified in Table 1. The difference between the height at the top of the blade edge
and the channel of the jig where the top of the specimen rests when being nicked is measured to ensure the proper setting of the
blade.
NOTE 13—Where it is desired to nick specimens to a notch depth required by Conditions B and C in Table 1 and the available jig has been designed for
D1693 − 21
FIG. 3 Bending Clamp Assembly
NOTE 1—X = 10.5 6 0.5 mm (0.41 6 0.02 in.)
FIG. 4 Transfer Tool Assembly
nicking specimens to a notch depth required by Condition A in Table 1, brass shim stock 0.21 mm (0.008 in.) thick may be used to make the more shallow
notch. Brass shim stock is cut wide enough so that it fits snugly inside the jig channel where the specimen rests when nicked. The length of the shim
should be such that it extends over the blade, around the end of the jig, and under the end so that the jig will rest on about 1 or 2 in. of the shim stock.
The weight of the jig resting on the shim stock prevents deformation of the shim stock during the nicking operation. An oblong hole long enough to fit
completely over the protruding blade is cut in the other end of the shim stock. Discard shim stock that becomes wrinkled or deformed in such a way as
to prevent the specimen from lying horizontal in the jig.
NOTE 14—In order to maintain notch consistency, it is recommended to keep the force applied to the jig handle constant. This can be done by applying
the force at the same location of the jig handle each time using a torque wrench.
NOTE 15—The notch depth correlates with the depth of blade setting, which is measured by a depth micrometer (see 10.2). The notch depth can be verified
by microtoming the cross section of the specimen followed by examining the slice under microscope. It also can be done by fracturing a notched specimen
after it is cooled with liquid nitrogen then examine the fracture surface under microscope.
NOTE 16—Check notch quality for straight edge, sharp
...