What is a key feature of thermosetting adhesives?

Thermosetting adhesives are characterized by their need for heat to initiate and complete the curing process. When heat is applied to these adhesives, they undergo a chemical reaction that causes them to change from a liquid or flexible state into a hard, solid state. This process is irreversible, meaning that once cured, thermosetting adhesives cannot be melted or remolded through heat again.

This property makes them particularly suitable for applications that require strong and durable bonds, as they form an inflexible and heat-resistant structure after curing. The requirement for heat during the curing process distinguishes them from thermoplastic adhesives, which can soften upon heating and can be reshaped and remolded multiple times.

In contrast, other features listed are not applicable to thermosetting adhesives. They do not soften with heat after curing, are not easily removable due to their strong bond, and are not initially fluid when cured. Instead, they remain solid once they achieve their final set state.