ASTM D7028-07 (2024) 通过动态力学分析（DMA）测定聚合物基复合材料玻璃化转变温度（DMA Tg）的标准试验方法

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Designation: D7028 −07 (Reapproved 2024)
Standard Test Method for
Glass Transition Temperature (DMA Tg) of Polymer Matrix
Composites by Dynamic Mechanical Analysis (DMA)
1
This standard is issued under the ﬁxed designation D7028; 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.
1. Scope
1.1 This test method covers the procedure for the determi-
nation of the dry or wet (moisture conditioned) glass transition
temperature (T
g
) of polymer matrix composites containing
high-modulus, 20 GPa (> 3 × 10
6
psi), ﬁbers using a dynamic
mechanical analyzer (DMA) under ﬂexural oscillation mode,
which is a speciﬁc subset of the Dynamic Mechanical Analysis
(DMA) method.
1.2 The glass transition temperature is dependent upon the
physical property measured, the type of measuring apparatus
and the experimental parameters used. The glass transition
temperature determined by this test method (referred to as
“DMA Tg”) may not be the same as that reported by other
measurement techniques on the same test specimen.
1.3 This test method is primarily intended for polymer
matrix composites reinforced by continuous, oriented, high-
modulus ﬁbers. Other materials, such as neat resin, may require
non-standard deviations from this test method to achieve
meaningful results.
1.4 The values stated in SI units are standard. The values
given in parentheses are non-standard mathematical conver-
sions to common units that are provided for information only.
1.5 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 appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
2
D3878 Terminology for Composite Materials
D4065 Practice for Plastics: Dynamic Mechanical Proper-
ties: Determination and Report of Procedures
D4092 Terminology for Plastics: Dynamic Mechanical
Properties
D5229/D5229M Test Method for Moisture Absorption Prop-
erties and Equilibrium Conditioning of Polymer Matrix
Composite Materials
E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
E1309 Guide for Identiﬁcation of Fiber-Reinforced
Polymer-Matrix Composite Materials in Databases (With-
drawn 2015)
3
E1434 Guide for Recording Mechanical Test Data of Fiber-
Reinforced Composite Materials in Databases (Withdrawn
2015)
3
E1471 Guide for Identiﬁcation of Fibers, Fillers, and Core
Materials in Computerized Material Property Databases
(Withdrawn 2015)
3
E1640 Test Method for Assignment of the Glass Transition
Temperature By Dynamic Mechanical Analysis
E1867 Test Methods for Temperature Calibration of Dy-
namic Mechanical Analyzers
3. Terminology
3.1 Deﬁnitions—Terminology D3878 deﬁnes terms relating
to polymer matrix composites. Terminology D4092 deﬁnes
terms relating to dynamic mechanical property measurements
on polymeric materials.
3.2 Symbols: E’ = storage modulus
E” = loss modulus
1
This test method is under the jurisdiction of ASTM Committee D30 on
Composite Materials and is the direct responsibility of Subcommittee D30.04 on
Lamina and Laminate Test Methods.
Current edition approved Jan. 1, 2024. Originally approved in 2007. Last
previous edition approved in 2015 as D7028 – 07
ε1
(2015). Published January 2024.
DOI: 10.1520/D7028-07R24.
2
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 ASTM website.
3
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
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.
1

tan δ=E”/E’ = tangent delta

DMA Tg = glass transition temperature deﬁned from dy-

namic mechanical analysis measurement

L= length of specimen

W= width of specimen

T= thickness of specimen

= peak temperature from tangent delta curve

4. Summary of Test Method

4.1 A ﬂat rectangular strip of laminate is placed in the DMA

equipment and oscillated at a nominal frequency of 1 Hz. The

specimen is heated at a rate of 5 °C ⁄min (9 °F ⁄min). The same

loading frequency and heating rate is used for both dry and wet

specimens (moisture conditioned) to allow for comparison.

The temperature at which a signiﬁcant drop in storage modulus

(E’) begins is assigned as the glass transition temperature

(DMA Tg). The peak temperature of the tangent delta curve

) is identiﬁed along with DMA Tg for comparison purposes.

5. Signiﬁcance and Use

5.1 This test method is designed to determine the glass

transition temperature of continuous ﬁber reinforced polymer

composites using the DMA method. The DMA Tg value is

frequently used to indicate the upper use temperature of

composite materials, as well as for quality control of composite

materials.

6. Interferences

6.1 The standard testing machine shall be of the Dynamic

Mechanical Analysis (DMA) type of instrument that operates

with forced oscillation and applies a ﬂexural loading mode

(either three-point bend or dual cantilever) to the test specimen.

Refer to Practice D4065 for a summary of various other DMA

practices. Other loading modes (such as tensile, torsion or

shear) may produce different test results. If another equipment

type or loading mode is used the non-standard approach shall

be described in the report and the test result recorded as

non-standard.

6.2 A ﬁxed frequency of 1 Hz is standard in this test method.

In general, for a given material, a higher testing frequency

produces a higher DMA Tg value than this standard, while use

of the resonance mode will yield a different DMA Tg that may

be either higher or lower than the standard. If a non-standard

frequency, or the resonance mode, is used, the non-standard

approach shall be described in the report and the test result

recorded as non-standard.

6.3 A heating rate of 5 °C ⁄min 61 °C ⁄min (9 °F ⁄min 6

2 °F ⁄min) is standard in this test method. A change in heating

rate will affect the glass transition temperature result; the

standard heating rate is the best available compromise for

comparing DMA Tg results of dry and wet laminates. If a

different heating rate is used it shall be described in the report

and the result recorded as non-standard.

NOTE 1—Users should be advised that a heating rate of 5 °C ⁄min

represents a compromise between various issues related to Tg measure-

ment precision and bias. It is widely known that heat transfer limitations

are more pronounced in DMA apparatus compared to other thermal

analysis techniques, such as differential scanning calorimetry (DSC) and

thermomechanical analysis (TMA). For greatest precision, it has been

recommended that heating rates be 2 °C ⁄min or less. Test Method E1640

speciﬁes a heating rate of 1 °C ⁄min. However, in many cases 5 °C ⁄min is

recommended as a compromise between Tg measurement accuracy and

test method convenience, especially for wet laminate measurements, since

the slower heating rate will cause specimen drying that will itself bias the

results.

6.4 Purge gas type and ﬂow rate and the position of the

thermocouple can affect the DMA Tg test result and shall be

noted and reported. The same conditions shall be used for both

calibration and testing runs. Instrumentation manufacturer

recommendations should be followed.

6.5 It is standard in this test method that one of the major

ﬁber directions shall be parallel to the length of the specimen.

The span-to-depth ratio, ply orientation, and ply stacking

sequence of a specimen with respect to the testing ﬁxture have

a profound effect on the DMA Tg result. A meaningful

comparison of data requires that the specimen conﬁguration be

the same. A non-standard specimen conﬁguration shall be

described in the report and the result recorded as non-standard.

6.6 The standard deﬁnition in this test method for DMA Tg

is based on intersecting two tangent lines from a semi-

logarithmic plot of the storage modulus versus temperature.

Other T

deﬁnitions typically produce different test results. For

example, a linear plot scale will result in a lower value of DMA

Tg. A non-standard DMA Tg deﬁnition shall be described in

the report and the result recorded as non-standard. For com-

parison purposes the peak temperature of the tangent delta

curve (T

) is identiﬁed along with DMA Tg.

7. Apparatus

7.1 Micrometer, suitable for reading to 0.025 mm (0.001 in.)

accuracy for measuring the specimen thickness and width.

7.2 Caliper, suitable for reading to 0.025 mm (0.001 in.)

accuracy for measuring the specimen length and instrument

clamping distance.

7.3 Dynamic Mechanical Analyzer (DMA), with oven ca-

pable of heating to above the glass transition temperature and

of controlling the heating rate to the speciﬁed value.

8. Sampling and Test Specimens

8.1 Two specimens shall be tested for each sample. If the

testing is part of a designed experiment, other sampling

techniques may be used if described in the test plan.

8.2 Consult the instrument manufacturer’s manual for speci-

men size. A span-to-thickness ratio greater than ten is recom-

mended. Specimen absolute size is not ﬁxed by this method as

various dynamic mechanical analyzers require different sizes.

Depending on the analyzer, typical specimen size can range

from 56 64 × 12 61 × 2.0 60.5 mm (2.21 60.16 × 0.47

60.04 × 0.08 60.02 in.) (L × W × T) to 22 61×361 ×

1.0 60.5 mm (0.9 60.04 × 0.12 60.04 × 0.04 60.02 in.).

8.3 One of the major ﬁber directions in the specimen shall

be oriented along the length axis of the specimen. It is standard

that one of the major ﬁber directions shall be parallel to the

length of the specimen, and specimens containing only off-axis

D7028 − 07 (2024)

plies shall not be used. Any deviations from the standard

orientation shall be reported and the test results noted as

non-standard.

8.4 The specimen surfaces shall be ﬂat, clean, straight, and

dry to prevent slippage in the grips and mitigate any effects due

to moisture. Opposite surfaces must be essentially parallel and

intersecting surfaces perpendicular. Tolerances in thickness and

width must be better than 62 %.

8.5 The selected sample shall be taken from a representative

portion of the laminate. Laminate edges or other irregularities

created in the laminate by mold or bagging techniques should

be avoided.

9. Calibration

9.1 The DMA equipment shall be calibrated in accordance

with Test Method E1867 for temperature signals and in

accordance with the equipment manufacturer’s recommenda-

tion for the storage modulus. The equipment must be calibrated

in the same loading mode as will be used for testing, either dual

cantilever or three-point bending. The temperature calibration

points must span the DMA Tg result.

10. Conditioning

10.1 Moisture has signiﬁcant effect on DMA Tg. Therefore,

it is recommended that the test specimens should be weighed

before and after DMA Tg testing to quantify the moisture

change in the specimen resulting from the DMA Tg test.

10.2 Dry Specimens—To minimize the presence of moisture

in the specimens, dry specimens must be conditioned prior to

testing by using either of the following techniques:

10.2.1 Dry the specimens in an oven in accordance with

Test Method D5229/D5229M, Procedure D, then stored until

test in a desiccator or sealed MIL-PRF-131

(or equivalent)

aluminized bag, or

10.2.2 Store the material in a desiccator or sealed alumi-

nized bag immediately after material curing (lamination),

where the material shall remain except for the minimum time

required for removal during specimen preparation and testing.

The maximum time between cure (lamination) and testing shall

be 30 days, after which, prior to testing, specimens shall be

oven-dried in accordance with 10.2.1.

10.3 Wet Specimens—Condition in accordance with Test

Method D5229/D5229M, Procedure B. The conditioned speci-

mens shall be tested within 30 minutes after removal from the

conditioning chamber, or stored in sealed MIL-PRF-131 (or

equivalent) aluminized bag until test.

11. Procedure

11.1 Test Specimen—Measure the specimen thickness and

width to 0.025 mm (0.001 in.) and record. Measure the

specimen length to 0.025 mm (0.001 in.) and record. Weigh the

specimen to the nearest milligram (0.001 g) and record.

11.2 Specimen Installation—Install the specimen in the

DMA test equipment oven based upon clamping method to be

employed.

11.3 Positioning of Specimen—Follow the manufacturer’s

procedure for positioning the specimen in the clamps.

Generally, the specimen should be centered between the clamp

faces and be parallel to the base of the instrument. Mount the

specimen in dual cantilever mode or three-point bending mode.

11.4 Heating Rate—The standard heating rate is 5 °C ⁄min

61 °C ⁄min (9 °F ⁄min 62 °F ⁄min). The same heating rate

shall be used for all samples whose results are to be compared.

Any deviations from this heating rate shall be noted in the

report and the result shall be reported as non-standard.

11.5 Frequency—The standard frequency to be used in this

standard is 1 Hz, and the instrument should be operated in

constant strain mode.

11.6 Strain Amplitude—The maximum strain amplitude

should be kept within the linear viscoelastic range of the

material. Strains of less than 0.1 % are standard.

11.7 Temperature Range—Program the run to begin at room

temperature or a temperature at least 50 °C (90 °F) below the

estimated DMA Tg and to end at a temperature at least 50 °C

(90 °F) above DMA Tg, but below decomposition temperature.

11.8 Purge Gas Flow Rate—Follow the manufacturer’s

manual or recommendations to set the purge gas ﬂow rate. Five

litres/minute (0.2 CFM) is a typical purge gas ﬂow rate setting.

For some types of dynamic mechanical analyzers, a purge gas

ﬂow setting is not required.

11.9 Thermocouple Positioning—Follow the manufacturer’s

manual or recommendations to position the thermocouple.

Typically the thermocouple should be as close to the sample as

possible.

11.10 Test—Conduct DMA Tg measurements using the

instrument settings speciﬁed and record the load and displace-

ment data as a function of temperature. Allow the oven to cool

before removing the specimen. Weigh the specimen after the

test to the nearest milligram (0.001 g) after the removal from

the oven and record.

11.11 Specimen Examination—Examine the specimen after

the test and inspect for any visual anomalies (that is,

delamination, blisters, cracks, etc.). Record any visual anoma-

lies observed.

12. Interpretation of Results

12.1 Glass Transition Temperature (DMA Tg)—Plot the

logarithm of storage modulus (E’) and linear tangent delta (tan

δ) versus the linear temperature (Fig. 1). During the glass

transition, the storage modulus of the composite material is

signiﬁcantly reduced. The DMA Tg is determined to be the

intersection of two tangent lines from the storage modulus by

this test method. The ﬁrst tangent line (Line A, Fig. 1) is

selected at a temperature before the transition. This tempera-

ture is designated as TA. The second tangent line (Line B, Fig.

1) is constructed at the inﬂection point to approximately the

midpoint of the storage modulus drop. This temperature is

MIL-PRF-131, Barrier Materials, Watervaporproof, Greaseproof, Flexible,

Heat-Sealable. Available at http://assist.daps.dla.mil or from the Standardization

Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA

19111-5094.

D7028 − 07 (2024)

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标签： #动态力学分析 #DMA测定 #聚合物基复合材料

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ASTM D7028-07 2024 Standard Test Method for Glass Transition Temperature (DMA Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA) 通过动态力学分析（DMA）测定聚合物基复合材料玻璃化转变温度（DMA Tg）的标准试验方法

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ASTM D7028-07 (2024) 通过动态力学分析（DMA）测定聚合物基复合材料玻璃化转变温度（DMA Tg）的标准试验方法

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