1、Designation: D3800 16Standard 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 number in parenthes
2、es 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 U.S. Department of Defense.1. Scope1.1 This test method covers the determination of the densityof high-modu
3、lus fibers and is applicable to both continuous anddiscontinuous fibers.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard may involve hazardous materials,operations, and equipment. This standard does not purp
4、ort toaddress all of the safety concerns, if 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. Refe
5、renced Documents2.1 ASTM Standards:2D891 Test Methods for Specific Gravity,Apparent, of LiquidIndustrial ChemicalsD1505 Test Method for Density of Plastics by the Density-Gradient TechniqueD3878 Terminology for Composite MaterialsD5229/D5229M Test Method for MoistureAbsorption Prop-erties and Equili
6、brium Conditioning of Polymer MatrixComposite MaterialsD6308 Guide for Identification of Composite Materials inComputerized Material Property Databases (Withdrawn1999)3E12 Terminology Relating to Density and Specific Gravityof Solids, Liquids, and Gases (Withdrawn 1996)3E177 Practice for Use of the
7、Terms Precision and Bias inASTM Test Methods3. Terminology3.1 DefinitionsTerminology 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 sh
8、allhave precedence over other standards.3.2 Symbols:3.2.1 sdensity of standard3.2.2 ldensity of liquid3.2.3 fdensity of fiber3.2.4 mfdensity of the measured fiber containing sizing3.2.5 mldensity of the measured liquid containing surfac-tant3.2.6 surdensity of surfactant3.2.7 szdensity of sizing3.2.
9、8 wdensity of water3.2.9 sstandard deviation3.2.10 M1weight of suspension wire in air3.2.11 M2weight of suspension wire in liquid (to immer-sion point)3.2.12 M3weight of suspension wire plus item whosedensity is to be determined (in air)3.2.13 M4weight of suspension wire plus item whosedensity is to
10、 be determined (in liquid)3.2.14 M3M1weight of item for density to be deter-mined in air3.2.15 M4M2weight of item for density to be deter-mined in liquid4. Summary of Test Method4.1 Procedure ABuoyancy (Archimedes) Method:4.1.1 The sample is weighed in air and weighed in a liquidthat will thoroughly
11、 wet the sample and is of a lower density.4.1.2 The difference in weight of the sample in the twomedia is the buoyancy force. This force is converted to sample1This test method is under the jurisdiction of ASTM Committee D30 onComposite Materials and is the direct responsibility of Subcommittee D30.
12、03 onConstituent/Precursor Properties.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 1979. Last previous edition approved in 2011 as D3800M 11. DOI:10.1520/D3800-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Se
13、rvice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Co
14、nshohocken, PA 19428-2959. United States1volume by dividing it by the liquid density. The sample weightin air divided by the sample volume equals the sample density.4.2 Procedure BSink-Float Technique:4.2.1 The sample is placed in a container containing a liquidthat will thoroughly wet the sample an
15、d is of a lower density.A liquid of higher density than the sample and miscible withthe first liquid is then added slowly to the container underconstant gentle mixing until the sample is suspended in themixture.4.2.2 The density of the resulting mixed liquid is deter-mined using either a hydrometer
16、or a pycnometer. The densityof the sample is equal to the density of the liquid in which thesample is suspended.4.3 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 d
17、evelopment level and is one of the materialproperties normally 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
18、 be used with lineal mass ofthe fiber to give an approximation 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 v
19、olume and void volume based onreinforcement mass and laminate 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 t
20、estmethod is very dependent on buoyancy, any entrapped 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 agit
21、ation.6.1.4 Removal of SizingA bias will exist if sizing 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.mf5100 2 x! f1xsz!100(1
22、)wherex = mass of sizing as a percentage of the total 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:ml5100 2 x! l1xsur!100(2)wherex = mass of surfactant as a p
23、ercentage of total mass of themeasured liquid.6.2 (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
24、ofthe container. The sample size should be within a 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.
25、2 Procedure A:7.2.1 Balance, analytical, capable of 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
26、 steel, approxi-mately 0.4 mm in diameter, cut and 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 560 Torr) canbe maintained.7.2.6 Density StandardA solid piece of borosilicate glass(density approximately 2.2 g/mL) of
27、known density to foursignificant figures as determined 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 recommen
28、ded.7.2.9 Immersion LiquidThe liquid used shall not 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,
29、 glass or other transparent container resis-tant to liquids used is recommended.7.3.2 Immersion LiquidsSee Notes 1 and 2. One liquidshould have a density less than the fiber, and the other greater,4A No. 19 “Pyrex” glass stopper with a 3.175-mm diameter hole bored throughthe top for suspension purpo
30、ses has proved satisfactory.5One suitable surfactant to use with water is Triton X manufactured by Rohmand Haas, Philadelphia, PA.D3800 162so 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). Bo
31、th of theseliquids pose hazards (see Section 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 determinationo
32、f the specific gravity of the liquid, the use 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
33、not available, determine the weight of the 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
34、in air until the thermometerreads 23C. Remove 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. Empt
35、y the pycnometer, dry, andthen fill and weigh with the other liquid in the same manner as was donewith the water. Calculate the specific gravity at 23C of the liquid, f,asfollows:l5 b 2 e!/w 2 e! (3)where:e = apparent weight of empty pycnometer,w = apparent weight of pycnometer filled with water at
36、23C, andb = apparent weight of pycnometer filled 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 m
37、easurements at temperatures other than 23/23C, 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, whe
38、nresolving disputes or performing subsequent analysis of extractor residue, a reagent grade reagent shall be used. Unless6One such reference is in CRC Handbook of Chemistry and Physics, CRC PressInc., Boca Raton, FL.FIG. 1 Density Apparatus (Alternative)D3800 163otherwise indicated, it is intended t
39、hat the reagents conform tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society where such specifications areavailable.78.1.1 Water, H2O, (deionized or distilled and degassed), maycontain a wetting agent such as glycerin or surfactant. This isthe safest reagent
40、found, and recommended for Procedure A.NOTE 3Reagents in 8.1.2 8.1.6 should be used if water is found tobe unsatisfactory 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 Alco
41、hol), CH3OH.8.1.4 o-dichlorobenzene, CH4Cl2.(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 2Aas “probably c
42、arcinogenic to humans.”)8.1.6 Trichloroethylene, CHClCCl2.(WarningAs of theapproval date of this test method, trichloroethylene was listedby the International Agency for Research on Cancer in Group1 as “carcinogenic to humans.”)9. Hazards9.1 This test method should be used only by laboratoryworkers
43、with general training in the safe handling of chemi-cals. 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
44、 data sheet for each material used,including reagent materials 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. Calibra
45、tion and Standardization11.1 All measuring equipment shall 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
46、a fiber. In general, no specialconditioning is needed for 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.7Reagent Chemicals, American Chemical Society Specifications, Amer
47、icanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USP
48、C), Rockville,MD.FIG. 2 Density Apparatus (Alternative)D3800 16413. Procedure13.1 Procedure ABuoyancy (Archimedes) Method):13.1.1 Equipment Assembly:13.1.1.1 The assembly of the apparatus is shown in Fig. 1 orFig. 2. The balance stand must be firmly secured to a stablesurface with the balance restin
49、g 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 to shield thisarea. If excessive vibration is observed while weighing, vibra-tion damping pads must be used.13.1.2 Density Standard CalibrationFill the immersionfluid container34 to78 full with freshly boiled water, which h
