Enthalpy of fusion

The enthalpy of fusion, also known as the heat of fusion or latent heat of melting, describes the amount of energy required to convert a plastic from the solid to the liquid state of aggregation. This process requires overcoming the binding forces between the macromolecules of which the plastic consists. When a plastic is heated, its temperature rises steadily up to a certain point, the melting point. At this point, the transition from the solid to the liquid state begins.

During this phase transition, the temperature of the material remains constant, even though heat continues to be supplied. The energy supplied is used to overcome the intermolecular forces that hold the macromolecules together in the solid state. This energy, which is necessary to break the solid bonds and bring the molecules into a liquid, more mobile state, is referred to as the enthalpy of fusion. It is a specific property of each material and varies depending on the type of plastic.