ASTM D3800-22

Standard Test Method for Density of High-Modulus Fibers

SIGNIFICANCE AND USE
5.1 Fiber density is useful in the evaluation of new materials at the research and development level and is one of the material properties normally given in fiber specifications.  
5.2 Fiber density is used to determine fiber strength and modulus of both a fiber bundle and an individual filament. These properties are based on load or modulus slope over an effective area. Fiber density may be used with lineal mass of the fiber to give an approximation of effective tow area. Tow area divided by the average number of filaments in a tow gives an approximation of the effective area of an individual filament.  
5.3 Fiber density is used as a constituent property when determining reinforcement volume and void volume based on reinforcement mass and laminate density.
SCOPE
1.1 This test method covers the determination of the density of high-modulus fibers and is applicable to both continuous and discontinuous fibers.  
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard may involve hazardous materials, operations, and equipment. 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. See Section 9 for additional information.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2022
• ICS: 83.120 - Reinforced plastics
• Technical Committee: D30 - Composite Materials
• Drafting Committee: D30.03 - Constituent/Precursor Properties

Relations

• Refers: ASTM D5229/D5229M-20 - Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• Effective Date: 01-Mar-2020
• Refers: ASTM D3878-19a - Standard Terminology for Composite Materials
• Effective Date: 15-Oct-2019
• Refers: ASTM D3878-19 - Standard Terminology for Composite Materials
• Effective Date: 15-Apr-2019
• Refers: ASTM D3878-18 - Standard Terminology for Composite Materials
• Effective Date: 01-Apr-2018
• Refers: ASTM D3878-16 - Standard Terminology for Composite Materials
• Effective Date: 01-Aug-2016
• Refers: ASTM D3878-15 - Standard Terminology for Composite Materials
• Effective Date: 01-Jul-2015
• Refers: ASTM D5229/D5229M-14e1 - Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• Effective Date: 15-May-2014
• Refers: ASTM D5229/D5229M-14 - Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• Effective Date: 15-May-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM D3878-07(2013) - Standard Terminology for Composite Materials
• Effective Date: 01-May-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM D5229/D5229M-12 - Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• Effective Date: 01-Feb-2012
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM D1505-10 - Standard Test Method for Density of Plastics by the Density-Gradient Technique
• Effective Date: 01-Jul-2010
• Refers: ASTM D5229/D5229M-92(2010) - Standard Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite Materials
• Effective Date: 01-May-2010

Overview

ASTM D3800-22 - Standard Test Method for Density of High-Modulus Fibers provides procedures for accurately determining the density of high-modulus fibers, both continuous and discontinuous. Developed by ASTM International, this test method is essential for characterizing fiber properties during research, development, and quality assurance processes. The density of fiber materials is a key property provided in fiber specifications, impacting the evaluation of mechanical properties, such as strength and modulus, as well as calculation of reinforcement and void volumes in composite applications.

Complying with internationally recognized standardization principles, ASTM D3800-22 offers multiple methods, including the well-established Archimedes (buoyancy) method and the sink-float technique, ensuring accurate and repeatable fiber density determination utilizing SI units.

Key Topics

• High-Modulus Fiber Density Testing: The standard covers test procedures for both single filaments and fiber bundles, critical in the analysis and specification of advanced material systems.
• Test Methods:
  • Procedure A - Archimedes Method: Relies on measuring sample mass in air and an immersion liquid to calculate density via buoyancy.
  • Procedure B - Sink-Float Technique: Involves adjusting liquid density until the fiber floats, allowing direct comparison between sample and liquid densities.
  • Procedure C: Refers to an alternative method outlined in ASTM D1505.
• Equipment and Materials: Specific guidance on required apparatus, such as analytical balances, immersion liquids (water, methanol, acetone, etc.), hydrometers, and vacuum desiccators.
• Sample Preparation and Conditioning: Best practices for avoidance of entrapped air, appropriate cleaning, and conditioning by fiber type are addressed to ensure accurate results.
• Calibration: All measuring instruments must have current, certified calibration records available for inspection.
• Health and Safety: The standard emphasizes the need for appropriate safety, health, and environmental procedures when handling potentially hazardous chemicals.

Applications

The density measurement of high-modulus fibers is vital across several advanced material and engineering industries, including:

• Materials Research and Development: Evaluation of new fiber materials, supporting innovation and verification of expected properties.
• Composite Material Design: Calculation of fiber strength, modulus, and estimation of effective areas (bundle or filament) for mechanical design.
• Quality Control in Manufacturing: Conformance checks in fiber and composite production processes ensuring fibers meet specification.
• Reinforcement and Void Volume Calculations: Accurate constituent property data is crucial for determining reinforcement volume and void content in composite laminates.
• Fiber Specification Documentation: Density is a standard property included in technical data sheets for carbon, aramid, and glass fibers.

These applications underline the importance of reliable fiber density data in both product development and quality assurance processes.

Related Standards

ASTM D3800-22 references and aligns with several key ASTM standards and guides, including:

• ASTM D891: Test Methods for Specific Gravity of Liquid Industrial Chemicals.
• ASTM D1505: Density of Plastics by the Density-Gradient Technique.
• ASTM D3878: Terminology for Composite Materials.
• ASTM D5229/D5229M: Moisture Absorption Properties and Conditioning of Polymer Matrix Composite Materials.
• ASTM D6308: Guide for Identification of Composite Materials in Databases.
• ASTM E177: Practice for Use of the Terms Precision and Bias in ASTM Test Methods.

Utilizing ASTM D3800-22 in conjunction with these related standards supports consistent, accurate, and globally recognized measurement and reporting of high-modulus fiber density.

Keywords: ASTM D3800-22, fiber density test, high-modulus fibers, buoyancy method, Archimedes method, composite material standards, fiber specification, materials testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3800 − 22
Standard Test Method for
Density of High-Modulus Fibers
This standard is issued under the fixed designation D3800; 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 (´) 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. Scope Computerized Material Property Databases (Withdrawn
1999)
1.1 This test method covers the determination of the density
E12 Terminology Relating to Density and Specific Gravity
ofhigh-modulusfibersandisapplicabletobothcontinuousand
of Solids, Liquids, and Gases (Withdrawn 1996)
discontinuous fibers.
E177 Practice for Use of the Terms Precision and Bias in
1.2 Units—The values stated in SI units are to be regarded
ASTM Test Methods
as standard. No other units of measurement are included in this
standard.
3. Terminology
1.3 This standard may involve hazardous materials,
3.1 Definitions—Terminology D3878 defines terms relating
operations, and equipment. This standard does not purport to
tocompositematerials.TerminologyE12definestermsrelating
address all of the safety concerns, if any, associated with its
to density. Practice E177 defines terms relating to statistics. In
use. It is the responsibility of the user of this standard to
theeventofaconflictbetweenterms,TerminologyD3878shall
establish appropriate safety, health, and environmental prac-
have precedence over other standards.
tices and determine the applicability of regulatory limitations
3.2 Symbols:
prior to use. See Section 9 for additional information.
3.2.1 ρ —density of standard
s
1.4 This international standard was developed in accor-
3.2.2 ρ —density of liquid
dance with internationally recognized principles on standard-
l
ization established in the Decision on Principles for the
3.2.3 ρ —density of fiber
f
Development of International Standards, Guides and Recom-
3.2.4 ρ —density of the measured fiber containing sizing
mf
mendations issued by the World Trade Organization Technical
3.2.5 ρ —density of the measured liquid containing surfac-
ml
Barriers to Trade (TBT) Committee.
tant
2. Referenced Documents
3.2.6 ρ —density of surfactant
sur
2.1 ASTM Standards: 3.2.7 ρ —density of sizing
sz
D891 TestMethodsforSpecificGravity,Apparent,ofLiquid
3.2.8 ρ —density of water
w
Industrial Chemicals
3.2.9 s—standard deviation
D1505 Test Method for Density of Plastics by the Density-
3.2.10 M —weight of suspension wire in air
Gradient Technique
D3878 Terminology for Composite Materials
3.2.11 M —weight of suspension wire in liquid (to immer-
D5229/D5229M Test Method for MoistureAbsorption Prop- sion point)
erties and Equilibrium Conditioning of Polymer Matrix
3.2.12 M —weight of suspension wire plus item whose
Composite Materials
density is to be determined (in air)
D6308 Guide for Identification of Composite Materials in
3.2.13 M —weight of suspension wire plus item whose
density is to be determined (in liquid)
This test method is under the jurisdiction of ASTM Committee D30 on
3.2.14 M –M —weight of item for density to be deter-
3 1
Composite Materials and is the direct responsibility of Subcommittee D30.03 on
mined in air
Constituent/Precursor Properties.
3.2.15 M –M —weight of item for density to be deter-
Current edition approved May 1, 2022. Published May 2022. Originally
4 2
approved in 1979. Last previous edition approved in 2016 as D3800 – 16. DOI:
mined in liquid
10.1520/D3800-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. 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
D3800 − 22
4. Summary of Test Method where
x = mass of sizing as a percentage of the total mass of the
4.1 Procedure A—Buoyancy (Archimedes) Method:
measured fiber.
4.1.1 The sample is weighed in air and weighed in a liquid
that will thoroughly wet the sample and is of a lower density.
6.1.5 Effect of Surfactant Density—The addition of a sur-
4.1.2 The difference in weight of the sample in the two
factant to a liquid may produce bias if not considered. The
media is the buoyancy force. This force is converted to sample
effect may be shown by the following equation:
volume by dividing it by the liquid density. The sample weight
100 2 y ρ 1y ρ
~ ! ~ !
l sur
in air divided by the sample volume equals the sample density.
ρ 5 (2)
ml
4.2 Procedure B—Sink-Float Technique:
where
4.2.1 The sample is placed in a container containing a liquid
y = mass of surfactant as a percentage of total mass of the
that will thoroughly wet the sample and is of a lower density.
measured liquid.
A liquid of higher density than the sample and miscible with
the first liquid is then added slowly to the container under
6.2 (Method A):
constant gentle mixing until the sample is suspended in the
6.2.1 Immersion Point—The distance the sample is lowered
mixture.
into the liquid and the overall liquid level should be the same
4.2.2 The density of the resulting mixed liquid is deter-
throughout determinations for Procedure A. This may be done
mined using either a hydrometer or a pycnometer. The density
by putting a line for the desired liquid level on the outside of
of the sample is equal to the density of the liquid in which the
the container. The sample size should be within a few grams
sample is suspended.
from one sample to another.
4.3 Procedure C—For an alternative method, which may be
7. Apparatus
used, see Test Method D1505.
7.1 General:
5. Significance and Use
7.1.1 Thermometer, capable of reading the test temperature
5.1 Fiberdensityisusefulintheevaluationofnewmaterials
during the test to 0.1 °C.
attheresearchanddevelopmentlevelandisoneofthematerial
7.1.2 Agitator—Stirrer or mixing propeller capable of
properties normally given in fiber specifications.
slowly agitating solution without test interference.
5.2 Fiber density is used to determine fiber strength and
7.2 Procedure A:
modulus of both a fiber bundle and an individual filament.
7.2.1 Balance, analytical, capable of weighing to 0.0001 g,
These properties are based on load or modulus slope over an
adapted for suspension weighing.
effective area. Fiber density may be used with lineal mass of
7.2.2 Balance Stand,dependingonthetypeofbalanceused;
the fiber to give an approximation of effective tow area. Tow
two recommended stands are shown in Figs. 1 and 2.
area divided by the average number of filaments in a tow gives
7.2.3 Laboratory Jack, heavy-duty precision.
an approximation of the effective area of an individual fila-
7.2.4 Suspension Wire, nickel or stainless steel, approxi-
ment.
mately0.4mmindiameter,cutandshapedtomatchthesystem
used.
5.3 Fiber density is used as a constituent property when
7.2.5 Vacuum Desiccator (with Pump)—An airtight con-
determining reinforcement volume and void volume based on
tainer in which a low vacuum (less than 75 kPa [560Torr]) can
reinforcement mass and laminate density.
be maintained.
6. Interferences
7.2.6 Density Standard—A solid piece of borosilicate glass
(density approximately 2.2 g/mL) of known density to four
6.1 General (All Methods):
significant figures as determined by water immersion. ANIST
6.1.1 Temperature—The temperature of the liquid shall
standard of this type (SRM 1825) is recommended.
remain constant within a tolerance of 61 °C, since liquid
7.2.7 Vacuum Pump or Aspirator, used to provide vacuum-
density changes with temperature.
to-vacuum desiccator.
6.1.2 Sample Wetting (Entrapped Air)—Since this test
7.2.8 Container, glass or other transparent container resis-
method is very dependent on buoyancy, any entrapped air in
tant to a liquid medium is recommended.
the sample will change the measured density and not give a
7.2.9 Immersion Liquid—The liquid used shall not dissolve
true material density. Ensure visually that the sample does not
or otherwise affect the specimen, but should wet it and have a
contain entrapped air bubbles.
specific gravity less than that of the specimen. The specific
6.1.3 Homogenous Mixture—The density of the liquid shall
gravity of the immersion liquid shall be determined shortly
be uniform, through suitable agitation.
before and after each use.
6.1.4 Removal of Sizing—A bias will exist if sizing is not
removed. In this case, the measured fiber density is a combi-
7.3 Procedure B:
nation of the density of the fiber and the sizing. The following
equation may be used to calculate the effect of the sizing on the
density of the material. A No. 19 “Pyrex” glass stopper with a 3.175 mm diameter hole bored through
the top for suspension purposes has proved satisfactory.
~100 2 x! ρ 1x~ρ !
f sz One suitable surfactant to use with water is Triton X manufactured by Rohm
ρ 5 (1)
mf
100 and Haas, Philadelphia, PA.
D3800 − 22
FIG. 1 Density Apparatus (Alternative)
thermometer reads 23 °C. Remove the drop of water at the tip of the side
7.3.1 Container, glass or other transparent container resis-
arm with a bit of filter paper, taking care not to draw any liquid from
tant to liquids used is recommended.
within the capillary. Place the cap over the side arm, wipe the outside
7.3.2 Immersion Liquids—See Notes 1 and 2. One liquid
carefully, and weigh the filled bottle again to the nearest 0.2 mg. Empty
should have a density less than the fiber, and the other greater,
the pycnometer, dry, and then fill and weigh with the other liquid in the
so when mixed they have the same density as the fiber. Two same manner as was done with the water. Calculate the specific gravity at
23 °C of the liquid, ρ, as follows:
suitable liquids are trichloroethylene and dibromomethane
l
(having densities of 1.464 and 2.477 g/mL). Both these liquids
ρ 5 b 2 e / w 2 e (3)
~ ! ~ !
l
pose hazards (see Section 8).
where:
7.3.3 Hydrometer, capable of reading liquid density.
e = apparent weight of empty pycnometer,
7.4 Procedure C—Use the apparatus described in Test
w = apparent weight of pycnometer filled with water at 23 °C, and
Method D1505. b = apparent weight of pycnometer filled with liquid at 23 °C.
If a constant-temperature bath is available, a pycnometer without a
NOTE 1—Standard deionized or distilled water need not be measured,
thermometer may be used.
but can be taken as a value from standard tables. For the determination
NOTE 2—One standard, which has been found satisfactory for this
of the specific gravity of the liquid, the use of a standard plummet of
purpose, is the Reimann Thermometer Plummet. These are normally
known volume (Note 3) orTest MethodA, C, or D ofTest Methods D891,
calibrated for measurements at temperatures other than 23 °C, so that
using the modifications required to give s
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3800 − 16 D3800 − 22
Standard Test Method for
Density of High-Modulus Fibers
This standard is issued under the fixed designation D3800; 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 (´) 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. Scope
1.1 This test method covers the determination of the density of high-modulus fibers and is applicable to both continuous and
discontinuous fibers.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.3 This standard may involve hazardous materials, operations, and equipment. 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 safety, health, and healthenvironmental practices and determine the applicability of regulatory limitations prior to use. See
Section 9 for additional information.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D891 Test Methods for Specific Gravity, Apparent, of Liquid Industrial Chemicals
D1505 Test Method for Density of Plastics by the Density-Gradient Technique
D3878 Terminology for Composite Materials
D5229/D5229M Test Method for Moisture Absorption Properties and Equilibrium Conditioning of Polymer Matrix Composite
Materials
D6308 Guide for Identification of Composite Materials in Computerized Material Property Databases (Withdrawn 1999)
E12 Terminology Relating to Density and Specific Gravity of Solids, Liquids, and Gases (Withdrawn 1996)
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
3. Terminology
3.1 Definitions—Terminology D3878 defines terms relating to composite materials. Terminology E12 defines terms relating to
density. Practice E177 defines terms relating to statistics. In the event of a conflict between terms, Terminology D3878 shall have
precedence over other standards.
This test method is under the jurisdiction of ASTM Committee D30 on Composite Materials and is the direct responsibility of Subcommittee D30.03 on
Constituent/Precursor Properties.
Current edition approved Nov. 1, 2016May 1, 2022. Published November 2016May 2022. Originally approved in 1979. Last previous edition approved in 20112016 as
D3800M – 11.D3800 – 16. DOI: 10.1520/D3800-16.10.1520/D3800-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3800 − 22
3.2 Symbols:
3.2.1 ρ —density of standard
s
3.2.2 ρ —density of liquid
l
3.2.3 ρ —density of fiber
f
3.2.4 ρ —density of the measured fiber containing sizing
mf
3.2.5 ρ —density of the measured liquid containing surfactant
ml
3.2.6 ρ —density of surfactant
sur
3.2.7 ρ —density of sizing
sz
3.2.8 ρ —density of water
w
3.2.9 s—standard deviation
3.2.10 M —weight of suspension wire in air
3.2.11 M —weight of suspension wire in liquid (to immersion point)
3.2.12 M —weight of suspension wire plus item whose density is to be determined (in air)
3.2.13 M —weight of suspension wire plus item whose density is to be determined (in liquid)
3.2.14 M – M —weight of item for density to be determined in air
3 1
3.2.15 M – M —weight of item for density to be determined in liquid
4 2
4. Summary of Test Method
4.1 Procedure A—Buoyancy (Archimedes) Method:
4.1.1 The sample is weighed in air and weighed in a liquid that will thoroughly wet the sample and is of a lower density.
4.1.2 The difference in weight of the sample in the two media is the buoyancy force. This force is converted to sample volume
by dividing it by the liquid density. The sample weight in air divided by the sample volume equals the sample density.
4.2 Procedure B—Sink-Float Technique:
4.2.1 The sample is placed in a container containing a liquid that will thoroughly wet the sample and is of a lower density. A liquid
of higher density than the sample and miscible with the first liquid is then added slowly to the container under constant gentle
mixing until the sample is suspended in the mixture.
4.2.2 The density of the resulting mixed liquid is determined using either a hydrometer or a pycnometer. The density of the sample
is equal to the density of the liquid in which the sample is suspended.
4.3 Procedure C—For an alternative method, which may be used, see Test Method D1505.
D3800 − 22
5. Significance and Use
5.1 Fiber density is useful in the evaluation of new materials at the research and development level and is one of the material
properties normally given in fiber specifications.
5.2 Fiber density is used to determine fiber strength and modulus both of both a fiber bundle and an individual filament. These
properties are based on load or modulus slope over an effective area. Fiber density may be used with lineal mass of the fiber to
give an approximation of effective tow area. Tow area divided by the average number of filaments in a tow gives an approximation
of the effective area of an individual filament.
5.3 Fiber density is used as a constituent property when determining reinforcement volume and void volume based on
reinforcement mass and laminate density.
6. Interferences
6.1 General (All Methods):
6.1.1 Temperature—The temperature of the liquid shall remain constant within a tolerance of 61°C,61 °C, since liquid density
changes with temperature.
6.1.2 Sample Wetting (Entrapped Air)—Since this test method is very dependent on buoyancy, any entrapped air in the sample will
change the measured density and not give a true material density. Ensure visually that the sample does not contain entrapped air
bubbles.
6.1.3 Homogenous Mixture—The density of the liquid shall be uniform, through suitable agitation.
6.1.4 Removal of Sizing—A bias will exist if sizing is not removed. In this case, the measured fiber density is a combination of
the density of the fiber and the sizing. The following equation may be used to calculate the effect of the sizing on the density of
the material.
100 2 x ρ 1x ρ
~ ! ~ !
f sz
ρ 5 (1)
mf
where
x = mass of sizing as a percentage of the total mass of the measured fiber.
6.1.5 Effect of Surfactant Density—The addition of a surfactant to a liquid may produce bias if not considered. The effect may be
shown by the following equation:
~100 2 x! ρ 1x~ρ !
l sur
ρ 5 (2)
ml
100 2 y ρ 1y ρ
~ ! ~ !
l sur
ρ 5 (2)
ml
where
x = mass of surfactant as a percentage of total mass of the measured liquid.
y = mass of surfactant as a percentage of total mass of the measured liquid.
6.2 (Method A):
6.2.1 Immersion Point—The distance the sample is lowered into the liquid and the overall liquid level should be the same
throughout determinations for Procedure A. This may be done by putting a line for the desired liquid level on the outside of the
container. The sample size should be within a few grams from one sample to another.
D3800 − 22
7. Apparatus
7.1 General:
7.1.1 Thermometer, capable of reading the test temperature during the test to 0.1°C.0.1 °C.
7.1.2 Agitator—Stirrer or mixing propeller capable of slowly agitating solution without test interference.
7.2 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 steel, approximately 0.4 mm in diameter, cut and shaped to match the system used.
7.2.5 Vacuum Desiccator (with Pump)—An airtight container in which a low vacuum (less than 75 kPa [560 Torr]) can be
maintained.
7.2.6 Density Standard—A solid piece of borosilicate glass (density approximately 2.2 g/mL) of known density to four significant
figures as determined by water immersion. A NIST standard of this type (SRM 1825) is recommended.
FIG. 1 Density Apparatus (Alternative)
A No. 19 “Pyrex” glass stopper with a 3.175-mm3.175 mm diameter hole bored through the top for suspension purposes has proved satisfactory.
D3800 − 22
FIG. 2 Density Apparatus (Alternative)
7.2.7 Vacuum Pump or Aspirator, used to provide vacuum-to-vacuum desiccator.
7.2.8 Container, glass or other transparent container resistant to a liquid medium is recommended.
7.2.9 Immersion Liquid—The liquid used shall not dissolve or otherwise affect the specimen, but should wet it and have a specific
gravity less than that of the specimen. The specific gravity of the immersion liquid shall be determined shortly before and after
each use.
7.3 Procedure B:
7.3.1 Container, glass or other transparent container resistant to liquids used is recommended.
7.3.2 Immersion Liquids—See Notes 1 and 2. One liquid should have a density less than the fiber, and the other greater, so when
mixed they have the same density as the fiber. Two suitable liquids are trichloroethylene and dibromomethane (having densities
of 1.464 and 2.477 g/mL). Both of these liquids pose hazards (see Section 8).
7.3.3 Hydrometer, capable of reading liquid density.
7.4 Procedure C—Use the apparatus described in Test Method D1505.
NOTE 1—Standard deionized or distilled water need not be measured, but can be taken as a value from standard tables. For the determination of the
specific gravity of the liquid, the use of a standard plummet of known volume (Note 3) or Test Method A, C, or D of Test Methods D891, using the
modifications required to give specific gravity at 23°C23 °C, is recommended. One suggested procedure is the following: If a constant temperature water
bath is not available, determine the weight of the clean, dry pycnometer with the thermometer to the nearest 0.1 mg on an analytical balance. Fill the
pycnometer with water cooler than 23°C.23 °C. Insert the thermometer stopper causing excess water to be expelled through the side arm. Permit the filled
bottle to warm in air until the thermometer reads 23°C.23 °C. Remove the drop of water at the tip of the side arm with a bit of filter paper, taking care
One suitable surfactant to use with water is Triton X manufactured by Rohm and Haas, Philadelphia, PA.
One such reference is in CRC Handbook of Chemistry and Physics, CRC Press Inc., Boca Raton, FL.
D3800 − 22
not to draw any liquid from within the capillary. Place the cap over the side arm, wipe the outside
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