ASTM D2765-95
(Test Method)Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics
SCOPE
1.1 The gel content (insoluble fraction) produced in ethylene plastics by crosslinking can be determined by extracting with solvents such as decahydronaphthalene or xylene. Such extraction test methods are described herein. They are applicable to crosslinked ethylene plastics of all densities, including those containing fillers, and all provide corrections for the inert fillers present in some of those compounds.
1.2 Test Method A, which permits most complete extraction in least time, is to be used for referee tests, but two alternative nonreferee Test Methods B and C are also described. The first of these differs from the referee test method only in sample preparation; that is, it requires use of shavings taken at selected points in cable insulation, for example, rather than the ground sample required by the referee test method. Because the shaved particles are larger, less total surface per sample is exposed to the extractant, so this test method ordinarily yields extraction values about 1 to 2% lower than the referee method. The second of the alternative test methods requires that a specimen in one piece be extracted in xylene at a constant temperature of 110°C. At this temperature and with a one-piece specimen, even less extraction occurs (from 3 to 9% less than the referee test method) but swell ratio (a measure of the degree of crosslinking in the gel phase) can be determined.
1.3 Extraction tests can be made on articles of any shape. They have been particularly useful for electrical insulations since specimens may be selected from those portions of the insulation most susceptible to insufficient crosslinking.
1.4 The values stated in SI units are to be regarded as the standard. The inch-pound units in parentheses are for information only. Note 1-ISO 10147 is similar to this test, but is not equivalent.
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. Specific precautionary statements are given in Sections 6, 10, and 25.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation:D2765–95
Standard Test Methods for
Determination of Gel Content and Swell Ratio of
1
Crosslinked Ethylene Plastics
This standard is issued under the fixed designation D2765; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific precau-
1.1 The gel content (insoluble fraction) produced in ethyl-
tionary statements are given in Sections 6, 10, and 25.
ene plastics by crosslinking can be determined by extracting
with solvents such as decahydronaphthalene or xylene. Such
2. Referenced Documents
extraction test methods are described herein. They are appli-
2.1 ASTM Standards:
cabletocrosslinkedethyleneplasticsofalldensities,including
D 297 Test Methods for Rubber Products—Chemical
thosecontainingfillers,andallprovidecorrectionsfortheinert
2
Analysis
fillers present in some of those compounds.
D618 Practice for Conditioning Plastics and Electrical
1.2 TestMethodA,whichpermitsmostcompleteextraction
3
Insulating Materials for Testing
in least time, is to be used for referee tests, but two alternative
3
D883 Terminology Relating to Plastics
nonreferee Test Methods B and C are also described. The first
3
D1603 Test Method for Carbon Black in Olefin Plastics
of these differs from the referee test method only in sample
D 1998 Specification for Polyethylene Upright Storage
preparation;thatis,itrequiresuseofshavingstakenatselected
3
Tank
points in cable insulation, for example, rather than the ground
4
D3351 Test Method for Gel Count of Plastic Film
samplerequiredbytherefereetestmethod.Becausetheshaved
E691 Practice for Conducting an Interlaboratory Study to
particles are larger, less total surface per sample is exposed to
5
Determine the Precision of a Test Method
the extractant, so this test method ordinarily yields extraction
values about 1 to 2% lower than the referee method. The
3. Terminology
second of the alternative test methods requires that a specimen
3.1 Definitions of Terms Specific to This Standard:
inonepiecebeextractedinxyleneataconstanttemperatureof
3.1.1 gel content—the percentage by mass of polymer
110°C. At this temperature and with a one-piece specimen,
insoluble in a specified solvent after extraction under the
even less extraction occurs (from 3 to 9% less than the referee
specified conditions.
test method) but swell ratio (a measure of the degree of
3.1.2 soluble—capable of being loosened or dissolved, sus-
crosslinking in the gel phase) can be determined.
ceptible of being dissolved in or as if in a fluid. (SeeWebster’s
1.3 Extraction tests can be made on articles of any shape.
Ninth New Collegiate Dictionary, 1988.)
They have been particularly useful for electrical insulations
3.1.3 swell ratio—the ratio of the gel volume in the swollen
since specimens may be selected from those portions of the
state to its volume in the unswollen state.
insulation most susceptible to insufficient crosslinking.
3.2 Terms as shown inTerminology D883 are applicable to
1.4 The values stated in SI units are to be regarded as the
this test method.
standard. The inch-pound units in parentheses are for informa-
tion only.
4. Summary of Test Methods
NOTE 1—There is no equivalent ISO Method.
4.1 Specimens of the crosslinked ethylene plastic are
weighed and then immersed in the extracting solvent at the
1.5 This standard does not purport to address all of the
temperature specified by the procedure selected and for the
safety concerns, if any, associated with its use. It is the
time designated by that procedure. After extraction, the speci-
responsibility of the user of this standard to establish appro-
mens are removed, dried, and reweighed as directed. The
1 2
These test methods are under the jurisdiction of ASTM Committee D-20 on Annual Book of ASTM Standards, Vol 09.01.
3
PlasticsandarethedirectresponsibilityofSubcommitteeD20.12onOlefinPlastics. Annual Book of ASTM Standards, Vol 08.01.
4
Current edition approved Nov. 10, 1995. Published January 1996. Originally Annual Book of ASTM Standards, Vol 08.02.
5
published as D2765–68. Last previous edition D2765–90. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
D2765–95
amountofmaterialextractediscalculatedand,ifdesired,
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.