ASTM E831 PDF

Using minimal force at a range of temperatures, TMA can be used to find a variety of thermal and mechanical properties, including thermal expansion. In most cases, TMA uses linear coefficient of thermal expansion to detect changes in material properties and structure. A small sample of polymeric material is heated on a quartz platform, and a rod applies a small amount of pressure. As the samples gets warmer, the material expands and the rod changes positions.

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A number in parentheses indicates the year of last reapproval. The test method may be used at lower or negative expansion levels with decreased accuracy and precision seeSection The temperature range may be extendeddepending upon the instrumentation and calibration materialsused.

No other units of measurement are included in thisstandard. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Referenced Documents2. Summary of Test Method4.

Current edition approved Aug. Published August Originallyapproved in Last previous edition approved in as E — United States The coefficient of linearthermal expansion can be calculated from these recorded data.

Significance and Use5. This test method uses a smaller specimenand substantially different apparatus than Test Methods Eand D Unless effects of moisture areto be studied, use of dry purge gas is recommended and is essential foroperation at subambient temperatures. The minimum output signals required forthermomechanical analysis are a change in linear dimension,temperature and time.

Test Specimens7. Lateral dimen-sions shall not exceed 10 mm. NOTE 2—Specimens of other dimensions may be used but dimensionsshall be reported. NOTE 3—It has been found with some materials that this level offlatness and parallelness cannot be attained.

Specimens that do not meetthese requirements may result in increased imprecision. Where some heat or mechanical treatment is applied to thespecimen prior to test, this should be noted in the report. NOTE 4—Some materials, particularly composites, may require heattreatment to condition the specimen prior to test to relieve stresses ordistortions.

Such heat treatment must be included in the report. The observed expansion must be corrected for thedifference in expansion between the specimen holder and probeobtained from a blank run in which no sample or a specimen ofthe material of construction of the probe is run see NOTE 5—Direct readout of zero position and specimen length using theanalyzer sensing element, where available, with a sufficient range has beenfound to be an accurate means of length determination.

Place the specimen temperature sensor in contact withthe specimen or as near to the specimen as possible. The refrigerant used for cooling shall not come intodirect contact with the specimen. Depending on thecompressibility of the specimen and the temperature range tobe investigated, a force of between 1 and mN 0. The actual incremental force, mass, or stress abovethat required to make contact with zero force shall be noted inthe report. NOTE 6—Other heating rates may be used but shall be noted in thereport.

NOTE 7—Normally, the expansion increases with the increase intemperature as shown in the schematic diagram of Fig. An abruptchange in slope of the expansion curve indicates a transition of thematerial from one state to another. NOTE 8—For best results, specimen temperature gradients should besmall. High heating rates, large specimen sizes, and low specimen thermalconductivity may lead to large specimen temperature gradients.

Theeffects of specimen temperature gradients may be compensated for bycorrection found through the use of suitable reference materials whosesize and thermal conductivity are close to that of the test specimen.

Precision and Bias Maximumimprecision in the calculated mean coefficient of linear thermalexpansion may be estimated from the imprecisions in theindividual measurements by the following equation.

EDMONDO DE AMICIS HEART PDF

Thermomechanical Analysis (TMA)

Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Link to Active This link will always route to the current Adtm version of the standard. Color Analysis ASTM D E E Pharmaceutical laboratory apparatus stability chambers, tablet disintegration, tablet dissolution, tablet hardness, V-blenders, Lab Equipment for Sale: This standard does not purport to address all of the safety concerns, if any, associated with its use. Users must determine whether an instrument complying with this method yields results that are useful to evaluate and characterize retroreflective specimens, or specimens having optical structures. Looking for a specific close-up? The X-Rite i7 Colorimeter is highly automated. Type text as it appears:: Standards can be obtained from appropriate standards authorities.

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