Isothermal calorimetry - Microcalorimetry

Purpose

Microcalorimetry is a direct method to measure release or consumption of heat from a sample. The result can be used to determine reaction kinetics or to estimate a material's propensity for self-heating. Tests can be made in closed ampoules or in ampoules with a controlled environment (humidity, oxygen concentration). The analysis of thermal power can be combined with analysis of gases.

Examples of studies performed by RISE are:

• Ageing of EPDM
• Degradation/self-heating of vitamins
• Self-heating of wood pellets
• Self-heating of contaminated insulation (lagging fires)
• Reactivity of plastic materials
• Phase change materials
• Determination of heat capacity
• Oxidiation of oils
• Self-heating of cutting fluids

Method

RISE has two different microcalorimeters: TAM Air and TAM III. If desired, tests can be done in an inert
atmosphere or at different moisture concentrations. 

Testing in TAM Air involves placing a small quantity of test material (up to a few grams) into a 20 ml ampoule which is closed and then lowered into one of the instrument’s eight channels. The ampoule is in contact with a heat flow sensor, which also senses the preset temperature in the instrument. Production of heat in the ampoule as a result of oxidation, biological activity or other exothermic process creates a temperature gradient across the sensor, generating a voltage that is directly
proportional to the thermal process occurring inside the ampoule. The method produces time resolved
results.

TAM III is a development of TAM Air. In TAM III it is possible to vary mositure and oxygen concentration in the headspace. It is also possible to perform tests in a 125 ml ampoule.

Tests can be conducted from 10 °C up to approximately 145 °C.

Deliveries

The result is summarised by RISE in a written report. The report can be written in Swedish or English.