Add Attachments to Content Item ‘ASTM D Glass Transition Temperature ( DMA Tg) of Polymer Matrix Composites by Dynamic Mechanical Analysis (DMA) . ASTM D Glass Transition Temperature (DMA Tg) of Polymer ASTM D has become a widely used test standard in many companies due to. ASTM D用DMA测试Tg_能源/化工_工程科技_专业资料。Designation: D – 07?1 Standard Test Method for Glass Transition.
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D — 07?
ASTM E A number in parentheses indicates the year of last reapproval. Other materials, such as neat d7208, may require non-standard deviations from this test method to achieve meaningful results.
The values given in parentheses are non-standard mathematical conversions to common units that are provided for information d708. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Dynamic Mechanical Proper- ties: Terminology D de? Summary of Test Method 4. Current edition approved Dec. The temperature at which a signi? The peak temperature of the tangent delta curve Tt is identi?
The DMA Tg value is frequently asfm to indicate the upper use temperature of composite materials, as well as for quality control of composite materials. Other loading modes such as tensile, torsion or shear may produce different test results. If another equipment type or loading mode ast used the non-standard approach shall be ashm in the report and the test result recorded as non-standard.
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 d708 the test result recorded as non-standard.
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 nonstandard.
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.
Test Method E speci? The span-to-depth ratio, ply orientation, and ply stacking sequence of a specimen with respect to the testing? A meaningful comparison of data requires that the specimen con? A non-standard specimen con? For example, a linear plot scale will result in a lower value of DMA Tg. A non-standard DMA Tg de? For comparison purposes the peak temperature of the tangent delta curve Tt is identi?
Sampling and Test Specimens 8.
If the testing is astk of a designed experiment, other sampling techniques may be used if described in the test plan. A span-to-thickness ratio greater than ten is recommended. Specimen absolute size is not? Depending on the analyzer, typical specimen size can range from 56 6 4 3 12 6 1 3 2.
It is standard that one of the major? Any deviations from the standard orientation shall be reported and the test results noted as non-standard.
Opposite surfaces must be essentially parallel and intersecting surfaces perpendicular.
ASTM D7028 – 07(2015)
Laminate edges or other irregularities created in the laminate by mold or bagging techniques should be avoided. The same conditions shall be used for both calibration and testing runs.
Instrumentation manufacturer recommendations should be followed. The equipment must be calibrated in the same d0728 mode as will be used for testing, either dual cantilever or three-point bending. The temperature calibration points must span the DMA Tg result. 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.
The maximum time between cure lamination asttm testing shall be 30 days, after which, prior to testing, specimens shall be oven-dried in accordance with The conditioned specimens shall be tested within 30 minutes after removal from the conditioning chamber, or stored in sealed MIL-PRF or equivalent aluminized bag until test. Measure the specimen length to 0. Weigh the specimen to the nearest milligram 0. 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. 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. Strains of less than 0.
For some types of dynamic mechanical analyzers, a purge gas? Typically the thermocouple should be as close to the sample as possible. Allow the oven to cool before removing the specimen.
Weigh the specimen after the test to the nearest milligram 0. Record aatm visual anomalies observed. Interpretation of Results During the glass transition, the storage modulus of the composite material is signi? The DMA Tg is determined to be the intersection of two tangent lines from the storage modulus by this test method. This temperature is designated as TA. The second tangent line Line B, Fig.
This temperature is designated as TB. The two tangent lines are intersected, and temperature corresponding to this intersection point is recorded as the DMA Tg. See Appendix X1 for additional guidelines to draw tangent lines.
A new or spare specimen shall be prepared from the same material package and tested to replace any specimens rejected per this paragraph. Should the results be retained, then these conditions shall be described in the test report. This could indicate that the sample was taken from a defective portion of the laminate. It is possible that more than one transition exists, but this should be dd7028 NOTE 2—Guides EEand E contain data reporting recommendations for composite materials and composite materials mechanical testing.
Precision and Bias 4 Table 1 presents the precision statistics generated from this study as de? The materials listed in Table 1 are de? These averages allow a relative comparison of the repeatability within laboratory precision and reproducibility between laboratory precision of the DMA Tg test parameters.
These values indicate that the material factors did not have a signi?
Examples are shown in this appendix to provide graphical illustrations of how to select the two tangent lines. It is ideal because the glass transition is clearly displayed.
Before the transition the storage modulus is relatively constant, the sigmoidal change during transition is clear, and after the transition the storage modulus is relatively constant. Using this approach the intersection point is drawn as shown in Fig.
If the two tangent lines are constructed from temperatures too close to the transition, the intersection is depicted as shown in Fig. On the other hand, if the two tangent lines are constructed at temperatures too far away from the transition, the intersection is depicted in Fig.
In this example the transition is less clear than the thermogram of Fig. Before the transition the storage modulus continues to slope downward and after the transition the storage modulus continues to slope downward.
Using the approach of this test method the intersection point is drawn as shown in Fig. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility.
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