ASTM F1634-95(2016)
(Practice)Standard Practice for In-Vitro Environmental Conditioning of Polymer Matrix Composite Materials and Implant Devices (Withdrawn 2017)
Standard Practice for <emph type="bdit">In-Vitro</emph> Environmental Conditioning of Polymer Matrix Composite Materials and Implant Devices (Withdrawn 2017)
SIGNIFICANCE AND USE
5.1 The conditioning procedures covered in this practice provide methods for saturating PMC specimens in a liquid environment prior to conducting other tests for property evaluation.
5.2 The conditioning may affect geometric and dimensional changes in specimens. In some severe cases, chemical changes may occur in the fiber, polymer and fiber-polymer interphase and interface.
5.3 Caution must be taken if Procedure B (10.2, Procedure B—Accelerated Moisture Saturation at Elevated Temperature) is followed to condition PMC specimens at an elevated temperature. Physical and chemical reactions in materials are normally temperature dependent. An increase in experimental temperature may accelerate a desirable moisture diffusion process. However, elevated temperatures above 37°C may also cause undesirable reactions that do not represent appropriate responses of materials at 37°C. Consequently, a pilot study is recommended in Procedure B to determine if a selected elevated temperature can be used for accelerated conditioning. If the properties of materials are determined to be irreversibly affected by this pilot study at the selected elevated temperature, then either an appropriate lower elevated temperature should be determined by repeating the pilot study, or Procedure B should not be used.
SCOPE
1.1 This practice covers two procedures for conditioning non-absorbable polymer matrix composite (PMC) materials and implant devices in a liquid environment to obtain a state of saturation.
1.2 The purpose of this practice is to standardize methods and reporting procedures for conditioning PMC materials and implant devices (PMC specimens) in a user selected liquid environment prior to conducting subsequent tests. It is not the purpose of this practice to determine the diffusion coefficients or actual saturation levels of a given liquid into the materials and devices. For these determinations, other procedures, such as Test Method D5229/D5229M, may be followed.
1.3 Diffusion of liquid into a solid material is a slow process. While the time necessary to achieve saturation at 37°C may be sufficiently short for thin specimens, such as fracture fixation plates, it may be prohibitively long in thick sections, such as femoral components for hip arthroplasty. However, the diffusion process may be accelerated at an elevated temperature. Consequently, two separate procedures (Procedures A and B) are presented in this practice. Procedure A covers exposing the specimen to the desired conditioning environment at 37°C. Procedure B prescribes a method to accelerate the diffusion process by conditioning the specimen at a selected elevated temperature.
1.4 This practice does not specify the test environment to be used for conditioning. However, the pH value of immersion liquid shall be maintained at 7.4 ± 0.2 to simulate the in vivo environment.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
WITHDRAWN RATIONALE
This practice covered two procedures for conditioning non-absorbable polymer matrix composite (PMC) materials and implant devices in a liquid environment to obtain a state of saturation.
Formerly under the jurisdiction of Committee F04 on Medical and Surgical Materials and Devices, this practice was withdrawn in June 2017. This standard is being withdrawn without replacement due to its limited use by industry.
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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: F1634 − 95 (Reapproved 2016)
Standard Practice for
In-Vitro Environmental Conditioning of Polymer Matrix
Composite Materials and Implant Devices
This standard is issued under the fixed designation F1634; 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 responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This practice covers two procedures for conditioning
bility of regulatory limitations prior to use.
non-absorbable polymer matrix composite (PMC) materials
and implant devices in a liquid environment to obtain a state of
2. Referenced Documents
saturation.
2.1 ASTM Standards:
1.2 The purpose of this practice is to standardize methods
D618 Practice for Conditioning Plastics for Testing
and reporting procedures for conditioning PMC materials and
D756 Practice for Determination of Weight and Shape
implant devices (PMC specimens) in a user selected liquid
ChangesofPlasticsUnderAcceleratedServiceConditions
environment prior to conducting subsequent tests. It is not the
(Withdrawn 1998)
purpose of this practice to determine the diffusion coefficients
D3878 Terminology for Composite Materials
or actual saturation levels of a given liquid into the materials
D5229/D5229M TestMethodforMoistureAbsorptionProp-
and devices. For these determinations, other procedures, such
erties and Equilibrium Conditioning of Polymer Matrix
as Test Method D5229/D5229M, may be followed.
Composite Materials
1.3 Diffusion of liquid into a solid material is a slow
process.Whilethetimenecessarytoachievesaturationat37°C
3. Terminology
may be sufficiently short for thin specimens, such as fracture
3.1 Definitions:
fixation plates, it may be prohibitively long in thick sections,
3.1.1 cumulative moisture content, M (%), n—the amount
t
such as femoral components for hip arthroplasty. However, the
of absorbed moisture in a material at a given time t, expressed
diffusion process may be accelerated at an elevated tempera-
as a percentage of the weight of absorbed moisture divided by
ture. Consequently, two separate procedures (ProceduresAand
the initial specimen weight, as follows:
B) are presented in this practice. ProcedureAcovers exposing
W 2 W
i b
the specimen to the desired conditioning environment at 37°C.
M,% 5 3100 (1)
t
W
Procedure B prescribes a method to accelerate the diffusion
b
process by conditioning the specimen at a selected elevated
where:
temperature.
W = current specimen weight, g, and
t
1.4 This practice does not specify the test environment to be
W = initial (baseline) specimen weight at t = 0 and stan-
b
used for conditioning. However, the pH value of immersion
dard laboratory atmosphere, g.
liquid shall be maintained at 7.4 6 0.2 to simulate the in vivo
3.1.2 liquid, n—water, saline solution, calf serum, or any
environment.
other liquid solution that is used to condition PMC specimens.
1.5 The values stated in SI units are to be regarded as
3.1.3 nominal saturated moisture content, M (%)—an ap-
s
standard. No other units of measurement are included in this
proximationoftheamountofmoistureabsorbedbyaspecimen
standard.
at saturation, expressed as a percentage of the weight of
1.6 This standard does not purport to address all of the
absorbed moisture at approximate saturation divided by the
safety concerns, if any, associated with its use. It is the initial specimen weight, as follows:
1 2
ThispracticeisunderthejurisdictionofASTMCommitteeF04onMedicaland For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Surgical Materials and Devices and is the direct responsibility of Subcommittee contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
F04.15 on Material Test Methods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved June 1, 2016. Published June 2016. Originally the ASTM website.
approved in 1995. Last previous edition approved in 2008 as F1634 – 95 (2008). The last approved version of this historical standard is referenced on
DOI: 10.1520/F1634-95R16. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1634 − 95 (2016)
W 2 W 6.3 Specimen Bag—Asealable, flexible, moisture-proof bag
s b
M,% 5 3100 (2)
s
made of material suitable for exposure to specimens that have
W
b
been removed from the conditioning bath for cooling prior to
where:
weighing. Bags that meet the requirement of MIL-B-131 have
W = specimen weight at approximate saturation, g, and
s
been found to be satisfactory for use in such applications.
W = initial(baseline)specimenweightat t = 0andstandard
b
6.4 Absorbent Cloth—Clean, non-linting absorbent cloth for
laboratory atmosphere, g.
use in wiping excess liquid from surface of specimens.
3.1.4 standard laboratory atmosphere, n— a laboratory
6.5 Gloves—Clean, non-linting gloves for use when han-
atmosphere having a temperature of 23 6 2°C and a relative
dling specimens.
humidity of 50 6 10 %.
6.6 pH Measurement System—An analytical system capable
4. Summary of Test Method
of measuring pH to within 60.1.
4.1 In ProcedureA, a specimen is immersed in a liquid bath
6.7 Differential Scanning Calorimeter—An analytical sys-
at 37 6 1°C with a pH value of 7.4 6 0.2.
tem capable of heating a specimen at a controlled rate while
measuring heat input and temperature.
4.2 In Procedure B, conditioning occurs in a liquid bath at a
selected elevated temperature.
7. Sampling and Test Specimens
4.3 Weight change is monitored over time until specimens
7.1 Preparation—Precaution shall be taken to avoid the
reach the nominal moisture saturation content.
entrapment of moisture in uneven surfaces, or delamination
4.4 Keep specimens in the conditioning bath for storage
due to inappropriate machining and manufacturing processes.
prior to subsequent tests.
7.2 Labeling—Label the specimen so as to be distinct from
each other in a manner that will both be unaffected by the test
5. Significance and Use
andnotinfluencethetestand,furthermore,willnotberemoved
5.1 The conditioning procedures covered in this practice
during conditioning.
provide methods for saturating PMC specimens in a liquid
environment prior to conducting other tests for property
8. Measurements of Test Specimens
evaluation.
8.1 The following measurements shall be made on speci-
5.2 The conditioning may affect geometric and dimensional
mens prior to immersion, after conditioning at the end of a test
changes in specimens. In some severe cases, chemical changes
procedure, and at any intermediate stage as prescribed in the
may occur in the fiber, polymer and fiber-polymer interphase
test procedures:
and interface.
8.1.1 Weight—The weight within 0.005 % of specimen
5.3 Caution must be taken if Procedure B (10.2, Procedure
weight.
B—Accelerated Moisture Saturation at Elevated Temperature) 8.1.2 Characteristic dimensions of specimens may be mea-
is followed to condition PMC specimens at an elevated
sured as a function of immersion time to determine the amount
temperature. Physical and chemical reactions in materials are of swelling induced by moisture absorption.
normally temperature dependent. An increase in experimental
9. Visual Examination
temperature may accelerate a desirable moisture diffusion
process. However, elevated temperatures above 37°C may also
9.1 Noticeable qualitative changes in surfaces, outline, and
cause undesirable reactions that do not represent appropriate
general appearance of the test specimen shall be recorded after
responses of materials at 37°C. Consequently, a pilot study is
each stage of the testing procedure. These changes include
recommended in Procedure B to determine if a selected
color, surface irregularities, odor, surface voids, delamination
elevated temperature can be used for accelerated conditioning.
and cracking. The immersion liquid should also be observed
If the properties of materials are determined to be irreversibly
for evidence of material that has leached from specimens or
affectedbythispilotstudyattheselectedelevatedtemperature,
holders, and evidence of bacterial or fungal contamination. If
then either an appropriate lower elevated temperature should
bacterial or fungal contamination is found, specimens should
be determined by repeating the pilot study, or Procedure B
be removed from the solution, washed with detergent and
should not be used.
water, rinsed, and placed in fresh solution. If contamination is
a recurring problem, antibacterial or antifungal agents must be
6. Apparatus
added to the solution; minimal amounts should be used as they
6.1 Balance—An analytical balance capable of measuring
may affect specimen properties.
weight of specimens to within a resolution of at least 0.005 %
of the total specimen weight. 10. Procedures
6.2 Conditioning Bath—A temperature-controlled liquid 10.1 Procedure A—Moisture Saturation Determination at
bath shall be capable of maintaining the required temperature 37°C:
to within 61°C. The bath shall be monitored either on an 10.1.1 Specimen Preconditioning—Bring the test specimens
automated continuous basis or on a manual basis at regular to a uniform 23 6 2°C after manufacturing process.
intervals. 10.1.2 Moisture Absorption:
F1634 − 95 (2016)
10.1.2.1 Record the initial (baseline) weight, W . decomposition temperature. If nonhydrous solutions are used
b
10.1.2.2 Place the specimen in the conditioning bath, which as the conditioning environment (that is, pure lipid), then a
similar procedure can be followed except the temperature
has previously reached the specified temperature 37 6 1°C.
The pH value of immersion liquid used shall be maintained at would now be governed by the boiling or decomposition
temperature of the given environment and specimen combina-
7.4 6 0.2 throughout the conditioning process and monitored
at least once a week. If the solution pH falls outside the tion.
designated range, the solution should be changed. The pH 10.2.2 Effect of Accelerated Temperature Conditioning:
should not be maintained by repeatedly adding buffer to the
10.2.2.1 Once T is determined from 10.2.1.1, at least five
a
same solution. This will change solution composition and may
samples representative of the specimen being evaluated should
affect specimen properties. Evaporation losses should be made
be conditioning at both T and 37°C and then tested to check
a
up with sterile deionized water if saline, serum, plasma, or
for conditioning temperature induced differences. Because
other hydrous medium is used as the conditioning environ-
conditioning may influence different material properties of
ment.
PMC specimens in different ways, the test implemented to
10.1.2.3 Monitor the weight gain of specimens over time.A check for differences between T and 37°C should closely
a
suggested schedule is to weigh each specimen every 24 h for
match the intended post-conditioning test that the PMC speci-
the first 120 h, then every 96 h.
men will be conditioned for. If T influences the properties in
a
10.1.2.4 At the end of each time interval, remove the
question, then a lower conditioning temperature must be
specimens from the conditioning bath and place them in the identified by repeating this procedure at selected lower tem-
specimenbag.Sealthebagandallowthespecimenstocometo
peratures in which the property is not influenced by condition-
laboratory standard temperature. Remove the specimens from ing. If the property is determined to be not influenced by T ,
a
the bag and wipe the specimens free of surface moisture with
then T can be used to accelerate the conditioning process for
a
an absorbent lint-free cloth. Wait for 10 min and measure the subsequent specimens.
weight of specimens to the required precision, and W, along
10.2.3 Accelerated Conditioning:
t
with the corresponding total elapsed time and the time interval
10.2.3.1 Follow the procedures outlined in 10.1.2 with the
since the previous measurement.
exception that the conditioning bath will be maintained at T 6
a
10.1.2.5 Return the specimens to the conditioning bath. The
1.0°C. The same time-measurement sequence as described in
specimens shall not be out of the conditioning bath for more
10.1.2 should be used to determine the minimum time, t ,
min
than 30 min and shall not be out of the specimen bag for more
when saturation is reached. The bath should be adequately
than 15 min.
sealedtominimizeevaporationlossandperiodicallymonitored
10.1.2.6 Calculate cumulative moisture content, M (%),
to ensure adequate bath depth is maintained for complete
t
using Eq 1 at each time interval and plot versus time.
immersion of samples. If the bath is physically sealed, a safe
10.1.2.7 The minimum time, t , required to reach nominal
mechanism of pressure relief (that is, pressure relief valve or
min
saturated moisture content, M , is the time at which the change releasable lid seal) must be provided to prevent pressure
s
in cumulative moisture content from the prior measurement is
build-up if the oven is accidentally overheated. Evaporation
less than 0.010 % of specimen weight for three consecutive losses should be made up with sterile deionized water if saline,
weighings with no less than 96 h of elapsed time between each
serum, plasma, or other hydrous medium is used as the
consecutive weighing. conditioning environment.
10.1.2.8 Following moisture saturation within the specified
10.2.3.2 Following moisture saturation within the specified
tolerance range, the specimen should be stored in a bath of the
tolerance range, the specimen should be stored in a bath of the
same fluid which is to be used for post-conditioning testing
same fluid which is to be used for post-conditioning testing
until the time the post-conditioning testing is conducted.
until the time the post-conditioning testing is conducted.
10.2 Procedure B—Accelerated Moisture Saturation at El-
11. Selection of Conditioning Procedure
evated Temperature:
10.2.1 Determination of Accelerated Temperature (T )
11.1 The choice between procedures should preferably be
a
Level:
based on the one that gives the most reproducible results.
10.2.1.1 Specimens should be first saturated in the condi-
tioning environment at 37°C and then evaluated by differential
12. Report
scanning calorimeter (DSC) evaluation over a temperature
12.1 Report the following information:
range of 37 to 120°C. The purpose of this is to determine if a
12.1.1 Description of the
...
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