ASTM D1442-06(2012)
(Test Method)Standard Test Method for Maturity of Cotton Fibers (Sodium Hydroxide Swelling and Polarized Light Procedures)
Standard Test Method for Maturity of Cotton Fibers (Sodium Hydroxide Swelling and Polarized Light Procedures)
SIGNIFICANCE AND USE
Information regarding the percentage of immature fibers is desirable because immature fibers: (1) break easily during processing; (2) have a tendency to form neps; (3) have a tendency to become entangled around particles of trash and leaf, thus making cleaning more difficult and increasing the amount of fiber removed with foreign matter; ( 4) adversely affect yarn and fabric appearance; and ( 5) may appear differently after dyeing.
Maturity has a high positive correlation with linear density, but genetic differences and differences in wall thickness caused by plant diseases, soil, and water conditions during the growing season interfere with this relationship. Thus two cottons having the same linear density, or having the same average wall thickness as indicated by air-flow instruments, may vary greatly in maturity, that is, a cotton having extremely variable wall thickness may contain more immature fibers than another cotton of the same Micronaire reading composed of fibers having very uniform wall thickness.
The Sodium Hydroxide Swelling (Procedure 1) has been used in judging other maturity tests such as the Causticaire and the differential dye methods, in which the individual fibers are not examined.
Finer distinctions between different degrees of fiber wall development can be made with the Polarized Light procedure than with the Sodium Hydroxide Swelling procedure. The Polarized Light procedure gives a view of the fiber in its natural state so that fibrillar structure, striations, reversals, etc., are clearly visible as are growth abnormalities and variations in wall thickness. This method may be preferred by botanists, geneticists, and plant physiologists, while the Sodium Hydroxide Swelling procedure may be preferred for routine testing of large numbers of samples. Technicians are more easily trained for the latter method. Arbitrary classification as to maturity must be made with both methods.
This method is not considered satisfactory for acceptance...
SCOPE
1.1 This test method covers the determination of the percentage of mature fibers in a sample of loose, chemically untreated cotton fibers, whether taken before processing or unravelled from a textile product.
1.2 This test method gives two optional procedures for determining maturity, as follows:
1.2.1 Procedure 1—Sodium Hydroxide Swelling.
1.2.2 Procedure 2—Polarized Light.
Note 1—For other test methods for the determination of maturity of cotton fibers refer to Test Methods D1464 and .
1.3 The values stated in SI units are to be regarded as standard. No other units of measure are included in this standard.
1.4 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.
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D1442 − 06 (Reapproved 2012)
Standard Test Method for
Maturity of Cotton Fibers (Sodium Hydroxide Swelling and
Polarized Light Procedures)
This standard is issued under the fixed designation D1442; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope D2480Test Method for Maturity Index and Linear Density
of Cotton Fibers by the Causticaire Method (Withdrawn
1.1 This test method covers the determination of the per-
1992)
centage of mature fibers in a sample of loose, chemically
D7139Terminology for Cotton Fibers
untreated cotton fibers, whether taken before processing or
unravelled from a textile product.
3. Terminology
3.1 For all terminology relating to D13.11, Cotton Fibers,
1.2 This test method gives two optional procedures for
refer to Terminology D7139.
determining maturity, as follows:
3.1.1 The following terms are relevant to this standard:
1.2.1 Procedure 1—Sodium Hydroxide Swelling.
cotton fiber maturity, immature fibers, in testing with sodium
1.2.2 Procedure 2—Polarized Light.
hydroxide solutions (See Fig. 1 and Fig. 2), immature fibers,
observed under polarized light, lumen, mature fibers, in testing
NOTE 1—For other test methods for the determination of maturity of
with sodium hydroxide solutions (see Fig. 3), mature fibers,
cotton fibers refer to Test Methods D1464 and D2480.
observed under polarized light (see Table 1), micronaire
1.3 The values stated in SI units are to be regarded as
reading, test specimen, in cotton maturity test.
standard. No other units of measure are included in this
3.2 For all other terminology related to textiles, refer to
standard.
Terminology D123.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 Fibers are laid parallel on a microscope slide, covered
priate safety and health practices and determine the applica-
with a cover glass, treated with a mounting medium, and the
bility of regulatory limitations prior to use.
magnified images are then classified as mature or immature
fibers.
2. Referenced Documents
4.2 The method offers two procedures for classifying the
2.1 ASTM Standards:
fibers as mature or immature:
D123Terminology Relating to Textiles
4.2.1 Procedure 1, Sodium Hydroxide Swelling, which uses
D1440Test Method for Length and Length Distribution of an 18% solution of sodium hydroxide as the mounting
medium and a laboratory microscope for viewing the fibers at
Cotton Fibers (Array Method)
a magnification of 400×.
D1447Test Method for Length and Length Uniformity of
4.2.2 Procedure 2, Polarized Light, which uses clear min-
Cotton Fibers by Photoelectric Measurement
eral oil as the mounting medium and requires a polarizing
D1464Practice for Differential Dyeing Behavior of Cotton
microscope giving a magnification of 100×. Fibers are classi-
D1776Practice for Conditioning and Testing Textiles
fied according to their second-order interference colors, using
a first-order (or full wave) retardation plate (Table 1).
ThistestmethodisunderthejurisdictionofASTMCommitteeD13onTextiles
5. Significance and Use
and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers.
Current edition approved July 1, 2012. Published August 2012. Originally
5.1 Informationregardingthepercentageofimmaturefibers
approved in 1952. Last previous edition approved in 2006 as D1442–06. DOI:
is desirable because immature fibers: (1) break easily during
10.1520/D1442-06R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1442 − 06 (2012)
FIG. 1 Mature Fiber
FIG. 2 Immature Fiber (Type A)
processing; (2) have a tendency to form neps; (3) have a
tendency to become entangled around particles of trash and
areclearlyvisibleasaregrowthabnormalitiesandvariationsin
leaf, thus making cleaning more difficult and increasing the
wall thickness. This method may be preferred by botanists,
amount of fiber removed with foreign matter; (4) adversely
geneticists, and plant physiologists, while the Sodium Hydrox-
affect yarn and fabric appearance; and (5) may appear differ-
ide Swelling procedure may be preferred for routine testing of
ently after dyeing.
large numbers of samples. Technicians are more easily trained
5.2 Maturity has a high positive correlation with linear
for the latter method. Arbitrary classification as to maturity
density, but genetic differences and differences in wall thick-
must be made with both methods.
nesscausedbyplantdiseases,soil,andwaterconditionsduring
5.5 This method is not considered satisfactory for accep-
the growing season interfere with this relationship. Thus two
tancetestingbecausebetweenlaboratoryprecisioncanbepoor.
cottons having the same linear density, or having the same
In some cases the purchaser and seller may have to test a
average wall thickness as indicated by air-flow instruments,
commercial shipment of one or more specific material by an
mayvarygreatlyinmaturity,thatis,acottonhavingextremely
appropriate method even though the method has not been
variablewallthicknessmaycontainmoreimmaturefibersthan
recommendedforacceptancetestingofcommercialshipments.
another cotton of the same Micronaire reading composed of
In such a case, if there are differences of practical significance
fibers having very uniform wall thickness.
between reported test results for two laboratories (or more),
5.3 TheSodiumHydroxideSwelling(Procedure1)hasbeen
comparative tests should be performed to determine if there is
usedinjudgingothermaturitytestssuchastheCausticaireand
a statistical bias between them, using competent statistical
the differential dye methods, in which the individual fibers are
assistance. As a minimum, ensure the test samples to be used
not examined.
are as homogeneous as possible, are drawn from the material
5.4 Finerdistinctionsbetweendifferentdegreesoffiberwall from which the disparate test result were obtained, and
development can be made with the Polarized Light procedure randomly assigned in equal numbers to each laboratory for
than with the Sodium Hydroxide Swelling procedure. The testing. The test results from the two laboratories should be
Polarized Light procedure gives a view of the fiber in its compared using statistical test for unpaired data, at a probabil-
natural state so that fibrillar structure, striations, reversals, etc., ity level chosen prior to the testing series. If a bias is found,
D1442 − 06 (2012)
6.1.7 Mounting Medium, sodium hydroxide (NaOH)
solution, 18%, sp gr 1.197 6 0.002 at 60 to 70°F (16 to 20°C)
in a dropping bottle.
6.2 Procedure 2:
6.2.1 Polarizing Microscope equipped with a polarizer, an
analyzer, a first-order retardation plate, a cross-hair eyepiece
mounted so that the hairs make a 45° angle with the plane of
polarization, a rotatable, mechanical stage, and a microscope
lamp. The magnification must be at least 100×.
6.2.2 Mounting Medium, clear mineral oil in a dropping
bottle.
6.2.3 Other Apparatus as specified in 6.1.2-6.1.6 for Proce-
dure 1.
7. Safety Precaution
7.1 The sodium hydroxide solution used in Procedure 1 is
caustic and corrosive. Use care in its preparation and applica-
tion to avoid contact with the skin or with equipment, espe-
cially the microscope objective, which may be permanently
damaged if the solution is not removed immediately following
contact. Clear water and a soft tissue will remove the solution.
8. Sampling and Preparation of Specimens
8.1 Three sources of specimens may be used with either
procedure.IfSuter-Webbarraylengthgroupsarenotavailable,
FIG. 3 Immature Fiber (Type B)
either of the other two sources of specimens may be used.
8.1.1 OptionA—Suter-WebbArrayLengthGroups—Prepare
A
TABLE 1 Colors of Cotton Fibers Viewed with Polarized Light
the array length groups as directed in Method D1440. From
Without Retardation Plate With Retardation Plate
1 3
one array discard the ⁄16-in. (1.6-mm) and ⁄16-in. (4.8-mm)
Fiber Subtractive
Additive Colors
Classification First Order Colors
length groups and any other length groups containing less than
Second Order First Order
1 mg of fibers. From each length group remaining, remove a
Mature light yellow yellow light yellow
bundle of approximately 100 fibers by lengthwise separation
white green yellow
Immature gray-blue blue orange-yellow
beginning with the longest group. Place the fibers on a
gray purple orange
microscope slide, spread them carefully to a width of 30 to 40
A
Classified according to Mary Anna Grimes, “Polarized Light Preferred for
mm.Coverthefiberswithacoverglassandapplyadropofthe
Maturity Tests,” Textile World, February, 1945.
mounting medium to one corner. Tap the cover glass to cause
the mounting medium to spread more rapidly and help prevent
airbubbles.Marktheslidewiththelengthgroupidentification.
The series of slides shall constitute a test specimen. Have a
either its cause must be found and corrected, or future test second operator prepare a second test specimen from a second
resultsforthatmaterialmustbeadjustedinconsiderationofthe array of the sample.
known bias.
NOTE 2—The sampling method described in 8.1.1 has been used for a
longer period of time and given slightly more reliable results than the
6. Apparatus and Reagents
other sampling methods.
6.1 Procedure 1: 8.1.2 Option B, Laboratory Blended Samples—Take a sub-
6.1.1 Microscope or Microprojector, which will give a sampleconsistingofasectionofsliverapproximately2in.(50
magnification of approximately 400×, equipped with a me- mm) long from the blended laboratory sliver. Twist one end of
chanical stage, microscope lamp, and viewing aid such as a the subsa
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