ASTM D746-07
(Test Method)Standard Test Method for Brittleness Temperature of Plastics and Elastomers by Impact
Standard Test Method for Brittleness Temperature of Plastics and Elastomers by Impact
SIGNIFICANCE AND USE
This test method establishes the temperature at which 50 % of the specimens tested fail when subjected to the conditions specified herein. The test provides for the evaluation of long-time effects such as crystallization, or those effects that are introduced by low-temperature incompatibility of plasticizers in the material under test. Plastics and elastomers are used in many applications requiring low-temperature flexing with or without impact. Use data obtained by this method to predict the behavior of plastic and elastomeric materials at low temperatures only in applications in which the conditions of deformation are similar to those specified in this test method. This test method has been found useful for specification purposes, but does not necessarily measure the lowest temperature at which the material is suitable for use.
FIG. 1 Dimensional Requirements Between Specimen Clamp and Striking Edge (Type A)
FIG. 2 Typical Clamp (Type A)
Note—Dimensions are in millimetres. FIG. 3 Dimensional Details of Striking Edge and Clamping Device, Type B (Positioning of Unnotched Test Specimen)
FIG. 4 Assembled Clamp with Test Specimens, Type B
SCOPE
1.1 This test method covers the determination of the temperature at which plastics and elastomers exhibit brittle failure under specified impact conditions. Two routine inspection and acceptance procedures are also provided.
Note 1—When testing rubbers for impact brittleness use Test Methods D 2137.
1.2 The values stated in SI units are to be regarded as the standard.
1.3 Due to the potential safety and environmental hazards associated with mercury-filled thermometers, the use of alternative temperature measuring devices (such as thermocouples and RTDs) is encouraged.
1.4 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.
Note 2—This test method and ISO 974 (E) are technically equivalent when using the Type B fixture and the Type III specimen, however, the minimum number of specimens that are required to be tested is significantly different when using this test method. The ISO method requires that a minimum of 100 specimens be tested.
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Designation: D746 − 07
StandardTest Method for
Brittleness Temperature of Plastics and Elastomers by
1
Impact
This standard is issued under the fixed designation D746; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 Department of Defense.
1. Scope* D2137TestMethodsforRubberProperty—BrittlenessPoint
of Flexible Polymers and Coated Fabrics
1.1 This test method covers the determination of the tem-
E1Specification for ASTM Liquid-in-Glass Thermometers
perature at which plastics and elastomers exhibit brittle failure
E77Test Method for Inspection and Verification of Ther-
under specified impact conditions. Two routine inspection and
mometers
acceptance procedures are also provided.
E608/E608MSpecification for Mineral-Insulated, Metal-
NOTE 1—When testing rubbers for impact brittleness useTest Methods
Sheathed Base Metal Thermocouples
D2137.
E1137/E1137MSpecification for Industrial Platinum Resis-
1.2 The values stated in SI units are to be regarded as the
tance Thermometers
standard.
2.2 ISO Standard:
ISO974(E)Plastics—DeterminationoftheBrittlenessTem-
1.3 Due to the potential safety and environmental hazards
3
perature by Impact
associated with mercury-filled thermometers, the use of alter-
native temperature measuring devices (such as thermocouples 2.3 ASTM Adjuncts:
4
Detailed Drawing of a Typical Clamp
and RTDs) is encouraged.
1.4 This standard does not purport to address all of the
3. Terminology
safety concerns, if any, associated with its use. It is the
3.1 General—The definitions of plastics used in this test
responsibility of the user of this standard to establish appro-
method are in accordance with Test Method D883 unless
priate safety and health practices and determine the applica-
otherwise specified.
bility of regulatory limitations prior to use.
3.2 brittleness temperature—that temperature, estimated
NOTE 2—This test method and ISO974 (E) are technically equivalent
statistically, at which 50% of the specimens would probably
when using the Type B fixture and the Type III specimen, however, the
minimum number of specimens that are required to be tested is signifi-
fail.
cantlydifferentwhenusingthistestmethod.TheISOmethodrequiresthat
a minimum of 100 specimens be tested.
4. Summary of Test Method
4.1 To determine the brittleness temperature, specimens are
2. Referenced Documents
secured to a specimen holder with a torque wrench. The
2
2.1 ASTM Standards:
specimen holder is immersed in a bath containing a heat-
D618Practice for Conditioning Plastics for Testing
transfer medium that is cooled. The specimens are struck at a
D832Practice for Rubber Conditioning For Low Tempera-
specified linear speed and then examined. The brittleness
ture Testing
temperature is defined as the temperature at which 50% of the
D883Terminology Relating to Plastics
specimens fail.
5. Significance and Use
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD20onPlastics
5.1 This test method establishes the temperature at which
and is the direct responsibility of Subcommittee D20.30 on Thermal Proper-
50% of the specimens tested fail when subjected to the
ties.30.07).
Current edition approved March 1, 2007. Published March 2007. Originally
approved in 1943. Last previous edition approved in 2004 as D746-04. DOI:
3
10.1520/D0746-07. ISO Standards Handbook 21,Vol1.ISOStandardsareavailablefromAmerican
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM 10036.
4
Standards volume information, refer to the standard’s Document Summary page on Adetailed drawing of a typical clamp may be obtained fromASTM Headquar-
the ASTM website. ters. Order Adjunct : ADJD0746.
*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
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D746 − 07
conditionsspecifiedherein.Thetestprovidesfortheevaluation have a clearance of 3.6 60.1 mm at and immediately follow-
oflong-timeeffectssuchascrystallization,orthoseeffectsthat ing impact. The clearance between the outside of the striking
areintroducedbylow-temperatureincompatibilityofplasticiz- edge and the clamp shall be 2.0 60.1 mm at impact. These
ers in the material under test. Plastics and elastomers are used dimensional requirements of the striking edge and clamping
inmanyapplicationsrequiringlow-temp
...
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