ASTM D5510-94
(Practice)Standard Practice for Heat Aging of Oxidatively Degradable Plastics
Standard Practice for Heat Aging of Oxidatively Degradable Plastics
SCOPE
1.1 This practice is intended to define the exposure conditions of plastics at various temperatures when exposed solely to hot air for extended periods of time. Only the procedures for heat exposure are specified, not the test method or specimen. The effect of heat on any particular property may be determined by selection of the appropriate test method and specimen; however, it is recommended that Practice D 3826 be used to determine the embrittlement endpoint, which is defined as that point in the history of a material when 75 % of the specimens tested have a tensile elongation at break of 5 % or less at an initial strain rate of 0.1 mm/mm min.
1.2 This practice should be used as a guide for comparing the thermal-aging characteristics of materials as measured by the change in some property of interest (that is, embrittlement by means of loss of elongation). It is very similar to Practice D3045 but is intended for use in evaluating plastics designed to be oxidized easily after use. The exposure times used for this practice will be significantly shorter than those used for Practice D3045.
1.3 The type of oven used can affect the results obtained from this practice. The user can use one of two methods for oven exposure. The results based on one method should not be mixed with those based on the other.
1.3.1 Procedure A: Gravity-Convection Oven--Recommended for film specimens having a nominal thickness not greater than 0.25 mm (0.010 in.).
1.3.2 Procedure B: Forced-Ventilation Oven--Recommended for specimens having a nominal thickness greater than 0.25 mm (0.010 in.).
1.4 This practice recommends procedures for comparing the thermal aging characteristics of materials at a single temperature. Recommended procedures for determining the thermal aging characteristics of a material at a series of temperatures for the purpose of estimating time to a defined property change at some lower temperature are also described. This practice does not predict thermal aging characteristics where interactions between stress, environment, temperature, and time control failure.
1.5 The values stated in SI units are to be regarded as the standard.
1.6 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--There is no ISO standard that is equivalent to this standard.
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Designation: D 5510 – 94 An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Practice for
Heat Aging of Oxidatively Degradable Plastics
This standard is issued under the fixed designation D 5510; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice is intended to define the exposure condi-
responsibility of the user of this standard to establish appro-
tions of plastics at various temperatures when exposed solely to
priate safety and health practices and determine the applica-
hot air for extended periods of time. Only the procedures for
bility of regulatory limitations prior to use.
heat exposure are specified, not the test method or specimen.
The effect of heat on any particular property may be deter-
NOTE 1—There is no ISO standard that is equivalent to this standard.
mined by selection of the appropriate test method and speci-
2. Referenced Documents
men; however, it is recommended that Practice D 3826 be used
to determine the embrittlement endpoint, which is defined as
2.1 ASTM Standards:
that point in the history of a material when 75 % of the
D 618 Practice for Conditioning Plastics and Electrical
specimens tested have a tensile elongation at break of 5 % or
Insulating Materials for Testing
less at an initial strain rate of 0.1 mm/mm min.
D 883 Terminology Relating to Plastics
1.2 This practice should be used as a guide for comparing
D 1870 Practice for Elevated Temperature Aging Using a
the thermal-aging characteristics of materials as measured by
Tubular Oven
the change in some property of interest (that is, embrittlement
D 2436 Specification for Forced-Convection Laboratory
by means of loss of elongation). It is very similar to Practice
Ovens for Electrical Insulation
D 3045 but is intended for use in evaluating plastics designed
D 3045 Practice for Heat Aging of Plastics Without Load
to be oxidized easily after use. The exposure times used for this
D 3593 Test Method for Molecular Weight Averages and
practice will be significantly shorter than those used for
Molecular Weight Distribution of Certain Polymers by
Practice D 3045.
Liquid Size-Exclusion Chromatography (Gel Permeation
1.3 The type of oven used can affect the results obtained
Chromatography GPC) Using Universal Calibration
from this practice. The user can use one of two methods for
D 3826 Practice for Determining Degradation End Point in
oven exposure. The results based on one method should not be
Degradable Polyolefins Using a Tensile Test
mixed with those based on the other.
E 145 Specification for Gravity-Convection and Forced-
1.3.1 Procedure A: Gravity-Convection Oven—
Ventilation Ovens
Recommended for film specimens having a nominal thickness
3. Terminology
not greater than 0.25 mm (0.010 in.).
1.3.2 Procedure B: Forced-Ventilation Oven—
3.1 Definitions—The definitions used in this practice are in
Recommended for specimens having a nominal thickness accordance with Terminology D 883.
greater than 0.25 mm (0.010 in.).
4. Significance and Use
1.4 This practice recommends procedures for comparing the
thermal aging characteristics of materials at a single tempera- 4.1 The correlation of results obtained from this practice to
ture. Recommended procedures for determining the thermal actual disposal environments (for example, composting) has
aging characteristics of a material at a series of temperatures not been determined, and, as such, the results should be used
for the purpose of estimating time to a defined property change only for comparative and ranking purposes.
at some lower temperature are also described. This practice 4.2 Degradable plastics exposed to heat may be subject to
does not predict thermal aging characteristics where interac- many types of physical and chemical changes. The severity of
tions between stress, environment, temperature, and time the exposures in both time and temperature determines the
control failure. extent and type of change that occurs. Short exposure times at
1.5 The values stated in SI units are to be regarded as the elevated temperatures generally serve to shorten the induction
standard. period of oxidatively degradable plastics during which the
1 2
This practice is under the jurisdiction of ASTM Committee D-20 on Plastics Annual Book of ASTM Standards, Vol 08.01.
and is the direct responsibility of Subcommittee D20.96 on Environmentally Annual Book of ASTM Standards, Vol 10.01.
Degradable Plastics. Annual Book of ASTM Standards, Vol 08.02.
Current edition approved Feb. 15, 1994. Published April 1994. Annual Book of ASTM Standards, Vol 14.02.
D 5510
depletion of antioxidants and stabilizers occurs. Physical prop- 4.10 In some situations, a material may be exposed to one
erties, such as tensile and impact strength and elongation and temperature for a particular period of time, followed by
modulus, may change during this induction period; however, exposure to another temperature for a particular period of time.
these changes are generally not due to molecular-weight This practice can be used for such applications. The heat-aging
degradation, but are merely a temperature-dependent response, curve of the first temperature should be derived, followed by
such as increased crystallinity or loss of volatile material, or derivation of the heat-aging curve for the second temperature
both. after exposure of samples to the first temperature.
4.11 There can be very large errors when Arrhenius plots or
4.3 Generally, short exposures at elevated temperatures may
equations based on data from experiments at a series of
drive out volatiles such as moisture, solvents, or plasticizers;
temperatures are used to estimate time to produce a defined
relieve molding stresses; advance the cure of thermosets;
property change at some lower temperature. This estimate of
increase crystallinity; and cause some change in color of the
time to produce the property change or failure must always be
plastic or coloring agent, or both. Normally, additional shrink-
accompanied by a 95 % confidence interval for the range of
age should be expected with a loss of volatiles or advance in
times possible based on the calculation or estimate.
polymerization.
4.4 Some plastic materials such as PVC may become brittle
5. Apparatus
due to loss of plasticizers or to molecular breakdown of the
5.1 Provisions for Conditioning, at specified standard con-
polymer. Polypropylene and its copolymers tend to become
ditions.
very brittle as molecular degradation occurs, whereas polyeth-
5.2 Oven.
ylene tends to become soft and weak before it embrittles with
5.2.1 Procedure A: Gravity-Convection Oven—
resultant loss in tensile strength and elongation.
Recommended for film specimens having a nominal thickness
4.5 Embrittlement of a material is not necessarily commen-
not greater than 0.25 mm (0.010 in.).
surate with a decrease in molecular weight. Test Method
5.2.2 Procedure B: Forced-Ventilation Oven—
D 3593 should be used to characterize any molecular-weight
Recommended for specimens having a nominal thickness
changes that may have occurred during thermal exposure.
greater than 0.25 mm (0.010 in.). When it is necessary to avoid
4.6 The degree of change observed will depend on the
contamination among specimens or materials, the tubular-oven
property measured. Different properties may not change at the
procedure, such as specified in Practice D 1870, may be
same rate. In most cases, ultimate properties, such as break
desirable. Oven apparatus shall be in accordance with Speci-
strength or break elongation, are more sensitive to degradation
fications D 2436 and E 145, Type 1A and Type IIB, with 50 6
than bulk properties such as modulus.
10 air changes/h and the requirements for uniformity extended
4.7 Effects of exposure may be quite variable, especially
to include the range of test temperatures. Recording instrumen-
when samples are exposed for long intervals of time. Factors
tation to monitor the temperature and humidity of exposure is
that affect the reproducibility of data are the degree of
recommended.
temperature control of the enclosure, humidity of the oven, air
5.3 Specimen Rack—A specimen rack or frame of suitable
velocity over the specimen, and exposure period. Errors in
design to allow ready air circulation around the specimens.
exposure are cumulative with time. Certain materials are
5.4 Test Equipment, in accordance with appropriate ASTM
susceptible to degradation due to the influence of humidity in
procedures to determine the selected property or properties.
long-term tests. Materials susceptible to hydrolysis (that is,
hydrolytically degradable plastics) may undergo degradation 6. Test Specimens
when subjected to long-term thermal tests due to moisture.
6.1 The number and type of test specimens required shall be
4.8 It should not be inferred that comparative material
in accordance with the ASTM test method for the specific
ranking is undesirable or unworkable. On the contrary, this
property to be determined; this requirement should be met at
practice is designed to provide information that can be used for
each time and temperature selected. Unless otherwise specified
such comparative purposes after appropriate physical property
or agreed upon by all interested parties, expose a minimum of
tests are performed following exposure. However, since it does
three replicates of each material at each time and temperature
not account for the influence of stress or environment that is
selected.
involved in most real life applications, the information ob-
6.2 The specimen thickness should be comparable to but no
tained from this practice must be used cautiously by the
greater than the minimum thickness of the intended applica-
designer, who must inevitably make material choices using
tion.
additional information, such as moisture, soil, and mechanical-
6.3 The method of specimen fabrication should be the same
action effects that are consistent with the requirements of the
as that for the intended application.
particular application.
6.4 All test specimens for a series of temper
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