Textile Glossary

Decomposition temperature

Definition

The decomposition temperature indicates the threshold at which a substance is irreversibly chemically degraded by the action of heat — meaning molecular chains are broken, volatile cleavage products are released, or the structure is permanently altered. It is not a sharp boundary but a temperature range that depends on the heating rate, the atmosphere, and the duration of exposure. Unlike the melting point, a substance that has exceeded its decomposition temperature cannot be used reversibly, because its chemical composition has been changed.

Use in the textile industry

In the textile industry, the decomposition temperature is an essential criterion when selecting fibers, finishing agents, and polymers for thermal processes such as heat-setting, calendering, or coating. It defines the upper limit of safe processing temperatures and determines whether a material is suitable for high-temperature applications such as protective clothing or technical textiles. The decomposition temperature of the substances used also plays a decisive role in evaluating the flame-retardant finishing and the fire behavior of textiles.

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Frequently asked question

The melting point describes the reversible transition of a crystalline or semi-crystalline polymer from the solid to the liquid state, during which the chemical structure is preserved. The decomposition temperature, by contrast, marks the onset of irreversible chemical degradation processes, after which the material permanently loses its original properties. Amorphous polymers have no defined melting point, which is why the decomposition temperature is often the more important thermal characteristic for these materials.

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