Scope:

This test technique helps identify potentially dangerous reactions, such as those involving volatile compounds, and calculate the temperatures and enthalpies of these reactions (heats). This test technique is indicated as an early test for determining the thermal risks of a chemical compound or combination that has not been characterized. 

Procedure:

A sample of the substance to be studied and thermally inert reference material is inserted in separate holders. Under an equilibrated environment, the sample and reference materials are concurrently heated at a regulated rate of 2 to 20 K/min. When a sample experienced a transition, including a change in enthalpy, the difference is signaled as a departure from the heat flow record’s original baseline. The integrated peak area (enthalpy) and the projected onset temperature (T_o) is determined and presented.

Specimen size:

A sample of 1 to 5 mg is often deemed sufficient if the response should be up to 8 mW.

Data:

Enthalpy of the reaction calculated as:
∆H = A/m
where:
∆H = enthalpy of reaction, J g-1
m = mass of the test specimen, mg
A = area of the reaction exotherm, J/g