1、Designation: D3800 99 (Reapproved 2010)Standard Test Method forDensity of High-Modulus Fibers1This standard is issued under the fixed designation D3800; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the determination of the densit
3、yof high-modulus fibers and is applicable to both continuous anddiscontinuous fibers.1.2 The values stated in SI units are to be regarded asstandard.1.3 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if
4、any, associated with itsuse. It is the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.See Section 9 for additional information.2. Referenced Documents2.1 ASTM Standards:2D891 Test
5、 Methods for Specific Gravity, Apparent, ofLiquid Industrial ChemicalsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for Moisture AbsorptionProperties and Equilibrium Conditioning of Polymer Ma-trix Composi
6、te MaterialsD6308 Guide for Identification of Composite Materials inComputerized Material Property Databases3E12 Terminology Relating to Density and Specific Gravityof Solids, Liquids, and Gases3E177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3. Terminology3.1 DefinitionsTer
7、minology D3878 defines terms relatingto composite materials. Terminology E12 defines terms relatingto density. Practice E177 defines terms relating to statistics. Inthe event of a conflict between terms, Terminology D3878 shallhave precedence over other standards.3.2 Symbols:rs= density of standardr
8、l= density of liquidrf= density of fiberrmf= density of the measured fiber containing sizingrml= density of the measured liquid containing sur-factantrsur= density of surfactantrsz= density of sizingrw= density of waters = standard deviationM1= weight of suspension wire in airM2= weight of suspensio
9、n wire in liquid (to immer-sion point)M3= weight of suspension wire plus item whosedensity is to be determined (in air)M4= weight of suspension wire plus item whosedensity is to be determined (in liquid)M3M1= weight of item for density to be determined inairM4M2= weight of item for density to be det
10、ermined inliquid4. Summary of Test Method4.1 GeneralUsing random selection techniques, a suitablesize sample of high-modulus fiber can be tested by any of thethree procedures described in this test method. Procedure Ausing water with a surfactant as the liquid medium is preferreddue to environmental
11、 and safety considerations. The other1This test method is under the jurisdiction of ASTM Committee D30 onCom-posite Materials and is the direct responsibility of Subcommittee D30.03 onConstituent/Precursor Properties.Current edition approved April 1, 2010. Published May 2010. Originallyapproved in 1
12、979. Last previous edition approved in 2004 as D3800 99 (2004).DOI: 10.1520/D3800-99R10.2For referenced 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 Summa
13、ry page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.methods shall not be used if Procedure A is adequate. Interimuse of Procedures B or C is allowed while a comparison ismade to results using Procedu
14、re A.4.2 Procedure ABuoyancy (Archimedes) Method:4.2.1 The sample is weighed in air and weighed in a liquidthat will thoroughly wet the sample and is of a lower density.4.2.2 The difference in weight of the sample in the twomedia is the buoyancy force. This force is converted to samplevolume by divi
15、ding it by the liquid density. The sample weightin air divided by the sample volume equals the sample density.4.3 Procedure BSink-Float Technique:4.3.1 The sample is placed in a container containing a liquidthat will thoroughly wet the sample and is of a lower density.A liquid of higher density than
16、 the sample and miscible withthe first liquid is then added slowly to the container underconstant gentle mixing until the sample is suspended in themixture.4.3.2 The density of the resulting mixed liquid is deter-mined using either a hydrometer or a pycnometer. The densityof the sample is equal to t
17、he density of the liquid in which thesample is suspended.4.4 Procedure CFor an alternative method, which may beused, see Test Method D1505.5. Significance and Use5.1 Fiber density is useful in the evaluation of new materialsat the research and development level and is one of the materialproperties n
18、ormally given in fiber specifications.5.2 Fiber density is used to determine fiber strength andmodulus both of a fiber bundle and an individual filament.These properties are based on load or modulus slope over aneffective area. Fiber density may be used with lineal mass ofthe fiber to give an approx
19、imation of effective tow area. Towarea divided by the average number of filaments in a tow givesan approximation of the effective area of an individual fila-ment.5.3 Fiber density is used as a constituent property whendetermining reinforcement volume and void volume based onreinforcement mass and la
20、minate density.6. Interferences6.1 General (All Methods):6.1.1 TemperatureThe temperature of the liquid shallremain constant within a tolerance of 61C, since liquiddensity changes with temperature.6.1.2 Sample Wetting (Entrapped Air)Since this testmethod is very dependent on buoyancy, any entrapped
21、air inthe sample will change the measured density and not give atrue material density. Ensure visually that the sample does notcontain entrapped air bubbles.6.1.3 Homogenous MixtureThe density of the liquid shallbe uniform, through suitable agitation.6.1.4 Removal of SizingA bias will exist if sizin
22、g is notremoved. In this case, the measured fiber density is a combi-nation of the density of the fiber and the sizing. The followingequation may be used to calculate the effect of the sizing on thedensity of the material.rmf5100 x! rf1 xrsz!100(1)wherex = mass of sizing as a percentage of the total
23、 mass of themeasured fiber.6.1.5 Effect of Surfactant DensityThe addition of a sur-factant to a liquid may produce bias if not considered. Theeffect may be shown by the following equation:rml5100 x! rl1 xrsur!100(2)wherex = mass of surfactant as a percentage of total mass of themeasured liquid.6.2 (
24、Method A):6.2.1 Immersion PointThe distance the sample is loweredinto the liquid and the overall liquid level should be the samethroughout determinations for Procedure A. This may be doneby putting a line for the desired liquid level on the outside ofthe container. The sample size should be within a
25、 few gramsfrom one sample to another.7. Apparatus7.1 General:7.1.1 Thermometer, capable of reading the test temperatureduring the test to 0.1C.7.1.2 AgitatorStirrer or mixing propeller capable ofslowly agitating solution without test interference.7.2 Procedure A:7.2.1 Balance, analytical, capable of
26、 weighing to 0.0001 g,adapted for suspension weighing.7.2.2 Balance Stand, depending on the type of balance used;two recommended stands are shown in Figs. 1 and 2.7.2.3 Laboratory Jack, heavy-duty precision.7.2.4 Suspension Wire, nickel or stainless steel, approxi-mately 0.4 mm in diameter, cut and
27、shaped to match the systemused.7.2.5 Vacuum Desiccator (with Pump)An airtight con-tainer in which a low vacuum (less than 75 kPa 22 in. Hg) canbe maintained.7.2.6 Density StandardA solid piece of borosilicate glass(density approximately 2.2 g/mL) of known density to foursignificant figures as determ
28、ined by water immersion.4A NISTstandard of this type (SRM 1825) is recommended.7.2.7 Vacuum Pump or Aspirator, used to provide vacuum-to-vacuum desiccator.7.2.8 Container, glass or other transparent container resis-tant to a liquid medium is recommended.7.2.9 Immersion LiquidThe liquid used shall no
29、t dissolveor otherwise affect the specimen, but should wet it and have aspecific gravity less than that of the specimen.5The specificgravity of the immersion liquid shall be determined shortlybefore and after each use.7.3 Procedure B:7.3.1 Container, glass or other transparent container resis-tant t
30、o liquids used is recommended.4A No. 19 “Pyrex” glass stopper with a 3.175-mm diameter hole bored throughthe top for suspension purposes has proved satisfactory.5One suitable surfactant to use with water is Triton X manufactured by Rohmand Haas, Philadelphia, PA.D3800 99 (2010)27.3.2 Immersion Liqui
31、dsSee Notes 1 and 2. One liquidshould have a density less than the fiber, and the other greater,so when mixed they have the same density as the fiber. Twosuitable liquids are trichloroethylene and dibromomethane(having densities of 1.464 and 2.477 g/mL). Both of theseliquids pose hazards (see Sectio
32、n 8).7.3.3 Hydrometer, capable of reading liquid density.7.4 Procedure CUse the apparatus described in TestMethod D1505.NOTE 1Standard deionized or distilled water need not be measured,but can be taken as a value from standard tables.6For the determinationof the specific gravity of the liquid, the u
33、se of a standard plummet ofknown volume (Note 3) or Test Method A, C, or D of Test Methods D891,using the modifications required to give specific gravity at 23C isrecommended. One suggested procedure is the following: If a constanttemperature water bath is not available, determine the weight of the
34、clean,dry pycnometer with the thermometer to the nearest 0.1 mg on ananalytical balance. Fill the pycnometer with water cooler than 23C. Insertthe thermometer stopper causing excess water to be expelled through theside arm. Permit the filled bottle to warm in air until the thermometerreads 23C. Remo
35、ve the drop of water at the tip of the side arm with a bitof filter paper, taking care not to draw any liquid from within the capillary.Place the cap over the side arm, wipe the outside carefully, and weigh thefilled bottle again to the nearest 0.2 mg. Empty the pycnometer, dry, andthen fill and wei
36、gh with the other liquid in the same manner as was donewith the water. Calculate the specific gravity at 23C of the liquid, rf,asfollows:rl5 b e!/w e! (3)where:e = apparent weight of empty pycnometer,w = apparent weight of pycnometer filled with water at 23C, andb = apparent weight of pycnometer fil
37、led with liquid at 23C.If a constant-temperature bath is available, a pycnometer without athermometer may be used.NOTE 2One standard, which has been found satisfactory for thispurpose, is the Reimann Thermometer Plummet. These are normallycalibrated for measurements at temperatures other than 23/23C
38、, so thatrecalibration is necessary for the purpose of these test methods. Calibra-tions at intervals of one week are recommended.8. Reagents8.1 Purity of ReagentsAs a minimum, a technical gradereagent is required to provide accurate results. However, whenresolving disputes or performing subsequent
39、analysis of extractor residue, a reagent grade reagent shall be used. Unlessotherwise indicated, it is intended that the reagents conform to6One such reference is in CRC Handbook of Chemistry and Physics, CRC PressInc., Boca Raton, FL.FIG. 1 Density Apparatus (Alternative)D3800 99 (2010)3the specifi
40、cations of the Committee on Analytical Reagents ofthe American Chemical Society where such specifications areavailable.78.1.1 Water,H2O, (deionized or distilled and degassed),may contain a wetting agent such as glycerin or surfactant. Thisis the safest reagent found, and recommended for Procedure A.
41、NOTE 3Reagents in 8.1.2-8.1.6 should be used if water is found to beunsatisfactory to accurately determine the density of the fiber. Otherreagents are listed in order of known hazard or toxicity.8.1.2 Acetone (2-Propanone),CH3CHOCH3.8.1.3 Methanol (Methyl Alcohol),CH3OH.8.1.4 o-dichlorobenzene,CH4Cl
42、2.(Warningo-dichlorobenzene has been identified as toxic and an irritant.)8.1.5 Dibromomethane,CH2Br2.(WarningAs of the ap-proval date of this test method, dibromomethane was listed bythe International Agency for Research on Cancer in Group 2Cas “toxic.”)8.1.6 Trichloroethylene, CHClCCl2.(WarningAso
43、ftheapproval date of this test method, trichloroethylene was listedby the International Agency for Research on Cancer in Group2D as a “cancer suspect agent” and mutagen.)9. Hazards9.1 This test method should be used only by laboratoryworkers with general training in the safe handling of chemi-cals.
44、A source of useful information is Prudent Practices in theLaboratory: Handling and Disposal of Chemicals, NationalAcademy Press, 1995, 448 pp., ISBN 0-309-05229-7.(WarningIn addition to other warnings, consult the appro-priate material safety data sheet for each material used,including reagent mater
45、ials and test specimen materials, forspecific recommendations on safety and handling.)10. Test Specimen10.1 A minimum of three test specimens shall be tested foreach sample.10.2 The test specimen weight shall be a minimum of 0.5 g.11. Calibration and Standardization11.1 All measuring equipment shall
46、 have certified calibra-tions that are current at the time of use of the equipment. Thecalibration documentation shall be available for inspection.12. Conditioning12.1 Test Method D5229/D5229M may be used to deter-mine equilibrium dryness of a fiber. In general, no specialconditioning is needed for
47、carbon fiber, less than 1 h at 100Cis needed for glass fibers, and approximately4hat100C isneeded for aramid fibers.12.2 Condition liquids to a test temperature, typically 23C.13. Procedure13.1 Procedure ABuoyancy (Archimedes) Method):13.1.1 Equipment Assembly:13.1.1.1 The assembly of the apparatus
48、is shown in Fig. 1 orFig. 2. The balance stand must be firmly secured to a stable7Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for Lab
49、oratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 2 Density Apparatus (Alternative)D3800 99 (2010)4surface with the balance resting on the stand directly over thehole provided for the suspension system. Place the immersionfluid container on the laboratory jack directly under thesuspension hook.13.1.1.2 To prevent stray air currents between the bottom ofthe balance and the top of the stand, it is advisable t
