ASTM D2115-04
(Practice)Standard Practice for Oven Heat Stability of Poly(Vinyl Chloride) Compositions
Standard Practice for Oven Heat Stability of Poly(Vinyl Chloride) Compositions
SIGNIFICANCE AND USE
Poly(vinyl chloride) compositions degrade by discoloration on prolonged exposure to heat. The degree of discoloration is related to the condition of exposure, such as length of period and temperature. When the conditions of exposure are fixed and controlled, then the relative resistance to discoloration due to heat of two or more compositions may be determined. The precision of heat stability testing is also dependent on the thickness of the specimens and the history of heat exposure prior to testing. This practice allows for control or the reporting of these variables.
This practice is particularly applicable for determining gross differences in the heat stabilities of poly(vinyl chloride) compositions that are detectable as a color change. It is not intended to measure absolute thermal stability. Although the observed color changes may be evidence of degradation, molecular degradation phenomena such as chain-scission or cross-linking may not be identifiable.
Note 2—While discoloration caused by exposure to elevated temperature is commonly regarded as evidence of degradation in poly(vinyl chloride) compositions, it must be borne in mind that some vinyl compositions may undergo substantial change in color without appreciable loss of mechanical strength, chemical resistance, etc., whereas others may resist change in color yet undergo substantial change in other properties. Therefore, resistance to discoloration should not be taken as sole evidence of thermal stability. It is recommended that this test be supplemented by others such as tensile strength and elongation, impact strength, and deflection temperature under load (for rigid compositions), Durometer hardness (for nonrigid compositions), and dilute solution viscosity, and that the test results before and after oven exposure be compared to determine the degree of degradation which has been produced in each of the properties measured.
This practice may be used to predict the relative discoloration in proce...
SCOPE
1.1 This practice lists procedures for determining the relative thermal stability of sheet or molded poly(vinyl chloride) compounds as indicated by discoloration due to exposure to an elevated temperature at controlled oven conditions.
1.2 A specimen preparation technique using a two-roll mill is provided for compositions that are not in molded or sheeted form.
1.3 This practice is not intended for use in purchasing specifications because the conditions of processing plastic compounds vary widely, and the degree of correlation of data obtained by this practice to process exposure has not been determined. However, despite this limitation, this practice does yield data of value in judging the comparative service quality of poly(vinyl chloride) compositions.
1.4 The values stated in SI units are to be regarded as the standard. The values in brackets are given 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.
Note 1—This standard is similar in content, but not technically equivalent to ISO 305-1990.
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Standards Content (Sample)
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Designation:D2115–04
Standard Practice for
1
Oven Heat Stability of Poly(Vinyl Chloride) Compositions
This standard is issued under the fixed designation D2115; 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 Department of Defense.
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1. Scope* Discoloration Method
1.1 This practice lists procedures for determining the rela-
3. Terminology
tive thermal stability of sheet or molded poly(vinyl chloride)
3.1 General—Definitions are in accordance with Terminol-
compounds as indicated by discoloration due to exposure to an
ogy D883 and abbreviations with Terminology D1600, unless
elevated temperature at controlled oven conditions.
otherwise indicated.
1.2 A specimen preparation technique using a two-roll mill
is provided for compositions that are not in molded or sheeted
4. Significance and Use
form.
4.1 Poly(vinyl chloride) compositions degrade by discolora-
1.3 This practice is not intended for use in purchasing
tiononprolongedexposuretoheat.Thedegreeofdiscoloration
specifications because the conditions of processing plastic
is related to the condition of exposure, such as length of period
compounds vary widely, and the degree of correlation of data
and temperature. When the conditions of exposure are fixed
obtained by this practice to process exposure has not been
and controlled, then the relative resistance to discoloration due
determined. However, despite this limitation, this practice does
to heat of two or more compositions may be determined. The
yield data of value in judging the comparative service quality
precision of heat stability testing is also dependent on the
of poly(vinyl chloride) compositions.
thickness of the specimens and the history of heat exposure
1.4 The values stated in SI units are to be regarded as the
priortotesting.Thispracticeallowsforcontrolorthereporting
standard.Thevaluesinbracketsaregivenforinformationonly.
of these variables.
1.5 This standard does not purport to address all of the
4.2 This practice is particularly applicable for determining
safety concerns, if any, associated with its use. It is the
gross differences in the heat stabilities of poly(vinyl chloride)
responsibility of the user of this standard to establish appro-
compositions that are detectable as a color change. It is not
priate safety and health practices and determine the applica-
intended to measure absolute thermal stability. Although the
bility of regulatory limitations prior to use.
observed color changes may be evidence of degradation,
NOTE 1—This standard is similar in content, but not technically
molecular degradation phenomena such as chain-scission or
equivalent to ISO 305–1990.
cross-linking may not be identifiable.
2. Referenced Documents
NOTE 2—While discoloration caused by exposure to elevated tempera-
2
ture is commonly regarded as evidence of degradation in poly(vinyl
2.1 ASTM Standards:
chloride) compositions, it must be borne in mind that some vinyl
D883 Terminology Relating to Plastics
compositions may undergo substantial change in color without appre-
D1600 Terminology for Abbreviated Terms Relating to
ciable loss of mechanical strength, chemical resistance, etc., whereas
Plastics
others may resist change in color yet undergo substantial change in other
2.2 ISO Standard:
properties. Therefore, resistance to discoloration should not be taken as
ISO305–1990 Plastics—Determination ofThermal Stability sole evidence of thermal stability. It is recommended that this test be
supplemented by others such as tensile strength and elongation, impact
of Poly(Vinyl Chloride), Related Chlorine-Containing
strength, and deflection temperature under load (for rigid compositions),
Polymers and Copolymers and Their Compounds—
Durometer hardness (for nonrigid compositions), and dilute solution
viscosity, and that the test results before and after oven exposure be
compared to determine the degree of degradation which has been
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This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
produced in each of the properties measured.
is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.
Current edition approved March 1, 2004. Published April 2004. Originally
4.3 This practice may be used to predict the relative
approved in 1962. Last previous edition approved in 2003 as D2115 - 92(03). DOI:
discoloration in processing, provided that the compositions in
10.1520/D2115-04.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of
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