ASTM D3929-03
(Test Method)Standard Test Method for Evaluating Stress Cracking of Plastics by Adhesives Using the Bent-Beam Method
Standard Test Method for Evaluating Stress Cracking of Plastics by Adhesives Using the Bent-Beam Method
SIGNIFICANCE AND USE
This test method is designed for obtaining a qualitative estimate of the compatibility of plastics and adhesives. Due to the many process variables associated with the fabrication of plastic parts, it is not possible to use this test as a substitute for compatibility tests on actual parts.
The detection of cracks or crazes may be determined with or without optical aid. Make comparisons only among tests employing crack detection methods of equivalent sensitivity.
SCOPE
1.1 This test method describes a procedure for determining the compatibility of adhesives with plastics based on whether the adhesive causes cracking of stressed samples.
1.2 Specimen configurations and test fixture designs are given.
1.3 This test method is suitable for products in the form of sheet or strip. It can also be used on injection molded tensile specimens or flexural bars.
1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3929 – 03
Standard Test Method for
Evaluating Stress Cracking of Plastics by Adhesives Using
1
the Bent-Beam Method
This standard is issued under the fixed designation D3929; 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.
1. Scope 3.2.2.1 Discussion—This is a form of localized yielding of
theplasticduetothecombinedactionofstressandanattacking
1.1 This test method describes a procedure for determining
medium. Initial crazing may be detectable only by inspection
the compatibility of adhesives with plastics based on whether
under magnification.
the adhesive causes cracking of stressed samples.
3.2.3 failure, n—an arbitrary point defined by the initial
1.2 Specimen configurations and test fixture designs are
detection of cracks or crazes.
given.
1.3 This test method is suitable for products in the form of
4. Summary of Test Method
sheet or strip. It can also be used on injection molded tensile
4.1 This test method involves the qualitative determination
specimens or flexural bars.
of the compatibility of adhesives with plastics by observing the
1.4 The values stated in SI units are to be regarded as the
effect of adhesives applied in the liquid state on stressed plastic
standard. The inch-pound units given in parentheses are for
specimens. Bars of plastic are bent in a three-point loading
information only.
fixture to cause a predetermined initial tensile stress on the
1.5 This standard does not purport to address all of the
surface of the bar. The liquid adhesive is then applied to the
safety concerns, if any, associated with its use. It is the
area of maximum stress which is checked periodically for
responsibility of the user of this standard to establish appro-
crazing or cracking.
priate safety and health practices and determine the applica-
4.1.1 Due to the stress relaxation behavior of certain plas-
bility of regulatory limitations prior to use.
tics, initial stress only can be determined and the stress level
2. Referenced Documents may decrease significantly during the course of the test.
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2.1 ASTM Standards:
5. Significance and Use
D638 Test Method for Tensile Properties of Plastics
5.1 This test method is designed for obtaining a qualitative
D790 Test Methods for Flexural Properties of Unreinforced
estimate of the compatibility of plastics and adhesives. Due to
and Reinforced Plastics and Electrical Insulating Materials
the many process variables associated with the fabrication of
D907 Terminology of Adhesives
plastic parts, it is not possible to use this test as a substitute for
3. Terminology compatibility tests on actual parts.
5.2 The detection of cracks or crazes may be determined
3.1 Definitions—Many of the terms in this test method are
with or without optical aid. Make comparisons only among
defined in Terminology D907.
tests employing crack detection methods of equivalent sensi-
3.2 Definitions of Terms Specific to This Standard:
tivity.
3.2.1 cracking, n—a continuous localized failure of the
plastic, leading to loss of structural integrity.
6. Apparatus
3.2.2 crazing, n—apparent fine cracks at or under the
3
6.1 Test Fixtures—Bent beam test fixtures (see Fig. 1) are
surface of a plastic.
designed to place the specimen in three-point bending. The
amount of deflection is adjustable as well as the loading span.
Other fixtures may be used as long as specimen deflection is
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This test method is under the jurisdiction of ASTM Committee D14 on
known.
AdhesivesandisthedirectresponsibilityofSubcommitteeD14.40onAdhesivesfor
6.2 The amount of deflection on the specimen is measured
Plastics.
Current edition approved April 10, 2003. Published May 2003. Originally by use of a dial gage indicator or a vernier caliper having a
´1
approved in 1980. Last previous edition approved in 1996 as D3929 – 96 . DOI:
10.1520/D3929-03.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Detailed drawings are shown in Figs. 3-5. Also necessary to complete the test
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Standards volume information, refer to the standard’s Document Summary page on fixture are the following parts: 2 pieces at 6 by 38 mm ( ⁄4 by 1 ⁄2-in.) dowel pins
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the ASTM website. and 2 pieces of M4–0.7 (8–32 unc) by 32 mm (1 ⁄4-in.) socket head cap screws.
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D3929 – 03
Tensile bars, such as Type I in Test Method D638, can also
beused.Specimensofrectangularsectionmayalsobecutfrom
...
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