ASTM D3015-95

Standard Practice for Microscopical Examination of Pigment Dispersion in Plastic Compounds (Withdrawn 2001)

SCOPE
1.1 This practice describes microscopical examination of plastic compounds to check quality of pigment dispersion. Thin sections of polymers are prepared for observation with transmitted light. Microscopical examination is normally made for grading or classification by comparison against observational standards.  
1.2 Operations are listed for practice generally applicable to many thermoplastic compounds. Details specific to wire- and cable-grade Type I polyethylene is given in Appendix X1. Note 1-There is no similar or equivalent ISO standard.
1.3 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.

General Information

• Status: Withdrawn
• Publication Date: 31-Dec-1994
• Withdrawal Date: 09-Jun-2001
• ICS: 83.140.99 - Other rubber and plastics products
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.40 - Optical Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 3015 – 95 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
Microscopical Examination of Pigment
Dispersion in Plastic Compounds
This standard is issued under the fixed designation D 3015; 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 of pigment dispersion. Black, weather-resistant polyethylene
serves as a good example where quality of the dispersion is
1.1 This practice describes microscopical examination of
indicative of weatherability which is achieved by effective
plastic compounds to check quality of pigment dispersion.
screening of ultraviolet light by the carbon black.
Thin sections of polymers are prepared for observation with
4.2 The test is directly applicable to plastic compounds that
transmitted light. Microscopical examination is normally made
are translucent in thin (microscopical) sections. Up to 5 %
for grading or classification by comparison against observa-
carbon black-filled polyethylene, for example, could be so
tional standards.
examined for dispersion. The test may also be employed
1.2 Operations are listed for practice generally applicable to
indirectly with opaque samples or pigment concentrates. Con-
many thermoplastic compounds. Details specific to wire- and
centrates (which are extended in use) may be diluted with base
cable-grade Type I polyethylene is given in Appendix X1.
resin to their final pigment level, as for example, by roll
NOTE 1—There is no similar or equivalent ISO standard.
milling, such that examination of test specimens may be made
1.3 This standard does not purport to address all of the with transmitted light. As such processing can effect improved
safety concerns, if any, associated with its use. It is the dispersion, dilution must not be employed without regard to
responsibility of the user of this standard to establish appro- end use of the material being sampled.
priate safety and health practices and determine the applica- 4.3 Examination and report are normally made with respect
bility of regulatory limitations prior to use. to observational standards which are not included in this
practice (see Section 7).
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
D 883 Terminology Relating to Plastics 5.1 Microscope, 100-power (103 eyepiece, 103 objective),
D 1238 Test Method for Flow Rates of Thermoplastics by unless otherwise agreed.
Extrusion Plastometer 5.2 Eyepiece Micrometer (optional), calibrated for magni-
F 412 Terminology Relating to Plastic Piping Systems fication employed. A stage micrometer (standard calibrating
slide), such as one having a 2-mm scale divided into units of
3. Terminology
0.01 mm (10 μm), may be employed to calibrate the eyepiece
3.1 Definitions—Terms applicable to this practice are de- scale.
fined in Terminologies D 883 and F 412.
5.3 Light Source, suitable for the microscope.
5.4 Microscope Slides, nominal 25 by 75 by 1 mm (1 by 3
4. Significance and Use
by 0.040 in.)
4.1 Examination is made because of the general relationship
NOTE 2—A liquid mixture of approximately the composition by volume
between observed quality on the microscopical scale and
given as follows has been found suitable for cleaning microscope slides.
overall serviceability, and to some extent the appearance, of the
After being cleaned, the slides shall be wiped dry with lint-free cleansing
plastic compound. The method may be employed to measure
tissue.
degree of dispersion of pigments, presence of foreign matter,
Ethyl alcohol (any grade) 85 %
Methyl alcohol (reagent grade) 10 %
spots of unpigmented resin, and resin degradation. Serviceabil-
Concentrated ammonium hydroxide (stock solution) 5 %
ity of a compounded plastic can be quite sensitive to the quality
5.5 Hot Plate, capable of maintaining temperature appropri-
ate for press-out of samples.
This practice is under the jurisdiction of ASTM Committee D-20 on Plastics
5.6 Lens-Cleaning Paper.
and is the direct responsibility of Subcommittee D20.40 on Optical Properties.
Current edition approved Sept. 10, 1995. Published November 1995. Originally 5.7 Pyrometer, or other suitable device capable of measur-
published as D 3015 – 72. Last previous edition D 3015 – 72 (1990).
ing surface temperatures of hot plate.
This revision includes additions of an ISO equivalency statement, a Terminology
5.8 Metal Shimstock, Brass, Aluminum, or Other Metal—
section, and a Keywords section.
2 5
Annual Book of ASTM Standards, Vol 08.01. Two pieces 3.8 cm by 7.9 mm (1.5 by ⁄16 in.), to control
Annual Book of ASTM Standards, Vol 08.04.
D 3015
thickness in pressing test specimens. Shimstock of 25-μm 7. Standardization
(0.001-in.) thickness has been found useful, but may be varied
NOTE 6—Observational standards will normally be employed for com-
to accommodate samples of different opacity.
parison, rating, and report of the microscopical examination. Such
5.9 Wood Block, with flat surface to be placed on the top
standards are not, however, included in this practice, but typically would
microscope slide of test specimen assembly to distribute force
be developed and employed according to purchaser-seller agreements, or
in pressing. preferably as specified in relevant material specifications.
7.1 Observational standards should be based on standard
6. Test Specimens
resins, and take the form of specially prepared microscope
6.1 Samples of concentrate may be diluted with unpig- slides or photomicrographs of such slides. Color photomicro-
mented base resin to the intended pigment content of the final
graphs may be necessary, but black and white should suffice
compound. The base resin used must be the same as that to be where only size and shape are important. Use of color
used in the final compound. Also as dilution can be performed photomicrographs would require definition of the illumination
in a variety of ways such as roll milling, passing through an used in viewing.
extruder, etc., the operation must be identified and the tech-
7.2 Standards should be numbered in an ascending order
nique performed in accordance with specific purchaser-seller
with quality from the best (one) to the worst (ten or other
agreements.
maximum number). Direct utilization and full effectiveness of
6.2 Prepare specimens on microscope slides for viewing.
this practice is achieved only when the point of minimum
6.2.1 Wash slides, knife blade, and all other items which acceptability is defined on this scale.
come in contact with samples. These items must be dried with 7.3 Dispersion standards must be established for each
cleansing tissue.
polymer-pigment system under evaluation.
6.2.2 Cover the top surface of the hot plate with clean
7.4 Additional standards may also be developed for agglom-
aluminum foil, and set controls for a temperature suitable to
erate size, spots of unpigmented resin, impurities, background,
press-out the polymer under test. Change the aluminum foil of
etc.
any polymer contamination, and clean prior to placing slides
NOTE 7—Color and texture of background are important clues to
on surface.
ultimate dispersion of pigments having particle size well below that
discernible at magnification of 100 power.
NOTE 3—The hot plate should be controlled at a temperature chosen
according to polymer type, its melt viscosity, and any other factor such as
8. Procedure
thermal sensitivity of the pigment system. Thermoplastics with melt flow
rates at condition 190/2.16 of Test Method D 1238, greater than 1.0 g/10
8.1 Place the specimen assembly on the stage of a micro-
min might well be pressed at 175 to 225°C, while those with melt flow
scope and compare at a magnification of 100 with the proper
rates less than 1.0 g/10 min might be pressed at 200 to 250°C. Poly(vinyl
observational standards using the suitable substage source of
chloride) should be pressed at
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