ASTM-E1981:98(R2020) pdf free download – Standard Guide for Assessing Thermal Stability of Materials by Methods of Accelerating Rate Calorimetry.
6.5 The use of the equations specified for the determination of kinetic parameters (see, for example, Appendix X 1) may not be suitable in many instances, especially when multiple reactions are involved.
6.6 Data may be obtained in the temperature range consistent with the calorimeter’s specifications and at pressures up to those consistent with the limitation of the pressure transducer or the material of construction of the bomb.
6.7 Modifications to the calorimeter can significantly alter the performance of the instrument. It is the user’s responsibility to assure that modifications do not alter the precision or accuracy of the instrument.
6.8 lithe thermal inertia (q)) factor for the experiment differs significantly from that of the system it is intended to simulate, any reaction mechanism observed experimentally may not be the same as the true reaction mechanism that exists in the system being simulated.
6.9 in the determination of kinetic parameters, the possibility of autocatalytic reaction mechanisms must be considered.
7. Hazards
7.1 The thermal stability characteristics, impact characteristics, (see Test Methods E476, E487, E537, E680, and E698, Practice E123l, and Ref (7)), or friction sensitivity characteristics of the sample, or a combination thereof, should be assessed, as it is often necessary to grind (see Note 1) or compact the sample prior to or during loading into the sample container. Additional physical properties of the sample may also need to be determined, such as sensitivity to electrostatic discharge.
.4 The apparatus shall employ the principles of adiabatic calorimetry to minimize heat loss from the reaction container to the surrounding environment.
8.5 The calorimeter shall be adequately shielded and vented in order to protect the operator from any sample container rupture or detonation within the calorimeter and from any resulting effluent. (see Section 7).
9. Procedure
9. 1 Calibration:
9. 1. 1 An instrument calibration should be carried out on a regular basis or whenever a major change has been made to the system (thermocouple or heater replacement. rupture of the sample container, unacceptable drift, and so forth) and should include the range of’ temperature used in testing substances.
9.1.2 An instrument calibration is best carried out using an empty, clean, light-weight sample container.
9.1.3 A number of compounds have been selected as suitable for use as system performance verification materials. As an example. Appendix X 1 contains a summary of the results of round robin testing for these compounds using an accelerating rate calorimeter. Other suitable devices may use the same or different calibration compounds.
9.2 Operating Procedure:
9.2.1 The sample to be tested is loaded into a sample container. Sample containers may be reused: however, it is the responsibility of the user to assure that the containers are properly cleaned prior to reuse. If stirring is to be carried out, a suitably equipped sample container must be used.
9.2.2 The general procedure described in the operating manual corresponding to the particular device being used should be followed.
9.2.3 After the test is completed and the system temperature.