1、Designation: D 1442 06Standard Test Method forMaturity of Cotton Fibers (Sodium Hydroxide Swelling andPolarized Light Procedures)1This standard is issued under the fixed designation D 1442; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the per-centage of mature fibers in a sample of loose
3、, chemicallyuntreated cotton fibers, whether taken before processing orunravelled from a textile product.1.2 This test method gives two optional procedures fordetermining maturity, as follows:1.2.1 Procedure 1Sodium Hydroxide Swelling.1.2.2 Procedure 2Polarized Light.NOTE 1For other test methods for
4、 the determination of maturity ofcotton fibers refer to Test Methods D 1464 and D 2480.1.3 The values stated in SI units are to be regarded asstandard. No other units of measure are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated w
5、ith its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 123 Terminology Relating to TextilesD 1440 Test Method for Leng
6、th and Length Distribution ofCotton Fibers (Array Method)D 1447 Test Method for Length and Length Uniformity ofCotton Fibers by Fibrograph MeasurementD 1464 Test Method for Differential Dyeing Behavior ofCottonD 1776 Practice for Conditioning and Testing TextilesD 2480 Test Method for Maturity Index
7、 and Linear Densityof Cotton Fibers by the Causticaire Method3D 7139 Terminology for Cotton Fibers3. Terminology3.1 For all terminology relating to D13.11, Cotton Fibers,refer to Terminology D 7139.3.1.1 The following terms are relevant to this standard:cotton fiber maturity, immature fibers, in tes
8、ting with sodiumhydroxide solutions (See Fig. 1 and Fig. 2), immature fibers,observed under polarized light, lumen, mature fibers, in testingwith sodium hydroxide solutions (see Fig. 3), mature fibers,observed under polarized light (see Table 1), micronairereading, test specimen, in cotton maturity
9、test.3.2 For all other terminology related to textiles, refer toTerminology D 123.4. Summary of Test Method4.1 Fibers are laid parallel on a microscope slide, coveredwith a cover glass, treated with a mounting medium, and themagnified images are then classified as mature or immaturefibers.4.2 The me
10、thod offers two procedures for classifying thefibers as mature or immature:4.2.1 Procedure 1, Sodium Hydroxide Swelling, which usesan 18 % solution of sodium hydroxide as the mountingmedium and a laboratory microscope for viewing the fibers ata magnification of 4003.4.2.2 Procedure 2, Polarized Ligh
11、t, which uses clear min-eral oil as the mounting medium and requires a polarizingmicroscope giving a magnification of 1003. Fibers are classi-fied according to their second-order interference colors, usinga first-order (or full wave) retardation plate (Table 1).5. Significance and Use5.1 Information
12、 regarding the percentage of immature fibersis desirable because immature fibers: (1) break easily duringprocessing; (2) have a tendency to form neps; (3) have atendency to become entangled around particles of trash andleaf, thus making cleaning more difficult and increasing theamount of fiber remov
13、ed with foreign matter; ( 4) adverselyaffect yarn and fabric appearance; and ( 5) may appeardifferently after dyeing.5.2 Maturity has a high positive correlation with lineardensity, but genetic differences and differences in wall thick-ness caused by plant diseases, soil, and water conditions during
14、1This test method is under the jurisdiction ofASTM Committee D13 on Textiles,and is the direct responsibility of Subcommittee D13.11 on Cotton Fibers.Current edition approved June 1, 2006. Published July 2006. Originally approvedin 1952. Last previous edition approved in 2000 as D 1442 00.2For refer
15、enced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、 C700, West Conshohocken, PA 19428-2959, United States.the growing season interfere with this relationship. Thus twocottons having the same linear density, or having the sameaverage wall thickness as indicated by air-flow instruments,may vary greatly in maturity, that is, a cotton having extremelyva
17、riable wall thickness may contain more immature fibers thananother cotton of the same Micronaire reading composed offibers having very uniform wall thickness.5.3 The Sodium Hydroxide Swelling (Procedure 1) has beenused in judging other maturity tests such as the Causticaire andthe differential dye m
18、ethods, in which the individual fibers arenot examined.5.4 Finer distinctions between different degrees of fiber walldevelopment can be made with the Polarized Light procedurethan with the Sodium Hydroxide Swelling procedure. ThePolarized Light procedure gives a view of the fiber in itsnatural state
19、 so that fibrillar structure, striations, reversals, etc.,are clearly visible as are growth abnormalities and variations inwall thickness. This method may be preferred by botanists,geneticists, and plant physiologists, while the Sodium Hydrox-ide Swelling procedure may be preferred for routine testi
20、ng oflarge numbers of samples. Technicians are more easily trainedfor the latter method. Arbitrary classification as to maturitymust be made with both methods.5.5 This method is not considered satisfactory for accep-tance testing because between laboratory precision can be poor.In some cases the pur
21、chaser and seller may have to test acommercial shipment of one or more specific material by anappropriate method even though the method has not beenrecommended for acceptance testing of commercial shipments.In such a case, if there are differences of practical significancebetween reported test resul
22、ts for two laboratories (or more),comparative tests should be performed to determine if there isa statistical bias between them, using competent statisticalassistance. As a minimum, ensure the test samples to be usedare as homogeneous as possible, are drawn from the materialfrom which the disparate
23、test result were obtained, andrandomly assigned in equal numbers to each laboratory fortesting. The test results from the two laboratories should becompared using statistical test for unpaired data, at a probabil-ity level chosen prior to the testing series. If a bias is found,either its cause must
24、be found and corrected, or future testresults for that material must be adjusted in consideration of theknown bias.6. Apparatus and Reagents6.1 Procedure 1:6.1.1 Microscope or Microprojector, which will give amagnification of approximately 4003, equipped with a me-chanical stage, microscope lamp, an
25、d viewing aid such as aEuscope or projection screen.6.1.2 Metal Comb, rake-type.6.1.3 Microscope Slides, 2 by 3 in. (50 by 75 mm), andappropriate cover glasses.FIG. 1 Mature FiberFIG. 2 Immature Fiber (Type A)D14420626.1.4 Forceps, Dissecting Needles, and Tweezers.6.1.5 Multiple Counter with totaliz
26、er or a pair of SingleCounters.6.1.6 Balance, with a capacity of 3 mg and a sensitivity of0.005 mg (needed for specimens taken from array lengthgroups only).6.1.7 Mounting Medium, sodium hydroxide (NaOH) solu-tion, 18 %, sp gr 1.197 6 0.002 at 60 to 70F (16 to 20C) ina dropping bottle.6.2 Procedure
27、2:6.2.1 Polarizing Microscope equipped with a polarizer, ananalyzer, a first-order retardation plate, a cross-hair eyepiecemounted so that the hairs make a 45 angle with the plane ofpolarization, a rotatable, mechanical stage, and a microscopelamp. The magnification must be at least 1003.6.2.2 Mount
28、ing Medium, clear mineral oil in a droppingbottle.6.2.3 Other Apparatus as specified in 6.1.2-6.1.6 for Pro-cedure 1.7. Safety Precaution7.1 The sodium hydroxide solution used in Procedure 1 iscaustic and corrosive. Use care in its preparation and applica-tion to avoid contact with the skin or with
29、equipment, espe-cially the microscope objective, which may be permanentlydamaged if the solution is not removed immediately followingcontact. Clear water and a soft tissue will remove the solution.8. Sampling and Preparation of Specimens8.1 Three sources of specimens may be used with eitherprocedure
30、. If Suter-Webb array length groups are not available,either of the other two sources of specimens may be used.8.1.1 Option ASuter-Webb Array Length GroupsPrepare the array length groups as directed in Method D 1440.From one array discard the116-in. (1.6-mm) and316-in.(4.8-mm) length groups and any
31、other length groups containingless than 1 mg of fibers. From each length group remaining,remove a bundle of approximately 100 fibers by lengthwiseseparation beginning with the longest group. Place the fibers ona microscope slide, spread them carefully to a width of 30 to 40mm. Cover the fibers with
32、a cover glass and apply a drop of themounting medium to one corner. Tap the cover glass to causethe mounting medium to spread more rapidly and help preventair bubbles. Mark the slide with the length group identification.The series of slides shall constitute a test specimen. Have asecond operator pre
33、pare a second test specimen from a secondarray of the sample.NOTE 2The sampling method described in 8.1.1 has been used for alonger period of time and given slightly more reliable results than theother sampling methods.8.1.2 Option B, Laboratory Blended SamplesTake a sub-sample consisting of a secti
34、on of sliver approximately 2 in. (50mm) long from the blended laboratory sliver. Twist one end ofthe subsample, hold it firmly and place the loose ends near theedge of a microscope slide. By means of a second slide heldperpendicularly, grip a few fibers, hold them lightly and pullthe subsample away
35、gently. Repeat the process until approxi-mately 200 fibers have been extracted. Pull the fibers from theentire width of the subsample and do not purposely discard anyfibers. Spread the extracted fibers and separate them as evenlyas possible, keeping them nearly parallel. A dissecting needlemay be us
36、ed to move the fibers while holding them lightly witha second slide or a cover glass. A minimum amount ofoverlapping will greatly facilitate fiber classification. Cover thefibers with a cover glass and apply a drop of the mountingmedium to one corner, tap the cover glass to cause the solutionto spre
37、ad more rapidly and help prevent air bubbles. Twotechnicians shall each prepare three slides in this way to securethe two specimens needed for a test.8.1.3 Option C, Fibrograph BeardsPrepare beards onFibrograph combs as directed in Test Method D 1447. Removethe beards from the two combs, divide each
38、 in half and usethree of these sections as subsamples. Roll up each of the threesections leaving the combed ends free. Prepare specimens asdescribed in 8.1.2 using the rolled-up sections of the beards assubsamples.FIG. 3 Immature Fiber (Type B)TABLE 1 Colors of Cotton Fibers Viewed with Polarized Li
39、ghtAFiberClassificationWithout Retardation Plate With Retardation PlateFirst OrderAdditive ColorsSubtractiveColorsSecond Order First OrderMature light yellowwhiteyellowgreenlight yellowyellowImmature gray-bluegraybluepurpleorange-yelloworangeAClassified according to Mary Anna Grimes, “Polarized Ligh
40、t Preferred forMaturity Tests,” Textile World, February, 1945.D14420639. Preparation of Microscope9.1 For Procedure 1, properly center and align the micro-scope, condenser, stage, and lighting system. Adjust the mi-croscope to obtain a magnification of approximately 4003.9.2 For Procedure 2, set the
41、 analyzer and polarizer atextinction (crossed polarizers) with the retardation plate re-moved. Insert the retardation plate with slow direction asindicated by the arrow on the plate, at 45 to the plane ofpolarization. Set the eyepiece so that one of the cross-hairs isparallel to the arrow of the ret
42、ardation plate.10. Conditioning10.1 If the arrays for Option A have not been stored in anair-conditioned laboratory, condition them in the standardatmosphere for testing textiles as directed in Practice D 1776before preparing and weighing the specimens. Preconditioningis not necessary.10.2 Condition
43、ing or preconditioning is not necessary forthe other sampling techniques, but a relative humidity between55 and 70 % facilitates the mounting of fibers.11. Procedure11.1 Have each of two technicians prepare and examine atest specimen in order to avoid variation associated withindividual technicians.
44、11.2 Place a prepared slide on the stage of the microscope,locate the last fiber on one side of the mounted fibers. Move theslide to bring the fibers into view, successively classify them asmature or immature, and record on the counters the number ofmature fibers and the total number of fibers on th
45、e slide.NOTE 3Intermediate degrees of maturity may be observed for Proce-dure 2 according to the information in Table 1.11.3 For the array test specimens, examine the fibers nearthe middle of their lengths, but for the randomly selectedspecimens view the fibers about 0.25 in. (6 mm) from the endheld
46、 down during extraction. Short fibers will otherwise beoverlooked.11.4 When there is difficulty in distinguishing betweenmature and immature fibers, proceed as directed in 11.4.1 or11.4.2.11.4.1 Procedure 1Focus up and down or move the slideso that a different portion of the fiber is visible. Move t
47、he slideback to its original position before moving to the next fiber.11.4.2 Procedure 2Observe the extinction characteristicsby removing the retardation plate and observing the appearanceof the fibers against a black background.11.5 Record the data from the counters, reset the counters tozero, and
48、examine each remaining slide.12. Calculation12.1 Recording and calculation of data are facilitated by theuse of work sheets such as those shown in Tables 2 and 3.12.2 Calculate the percentage of mature fibers as directed inthe appropriate table. Figures for Table 2, column 6 (Weight ofLength Group)
49、may be taken from the array data sheet (Fig. 2,Test Method D 1440).TABLE 2 Work SheetMaturity of Cotton Fibers (Array Sample)Test No. . Date .Sample Marketing and Description:(1)Length(2)W1Weight ofFibers onSlide(3)N1Number ofFibers onSlide(4)N2Number ofMatureFibers onSlide(5)M1Maturity(N2/N1)3100(6)WWeightof Com-binedLengthGroups(7)NNumber ofFibers inLengthGroupWN1/W1(8)(NM1)116 in. mg percent mg41393735333129272523211917151311975TotalsMaturity: M = (NM1)/(N = . percentD144206413. Report13.1 State that the tests were made as directed in TestMethod D 1442. Descri
