Final answer:
The reaction that transforms elastomeric impression materials into a rubberlike state is known as vulcanization, a process that makes materials more durable and elastic through the addition of sulfur or similar agents.
Step-by-step explanation:
The reaction that changes elastomeric impression materials from a paste into a rubberlike material is called vulcanization. This is a chemical process where materials, such as natural rubber, are heated with sulfur or other similar curatives or accelerators, which lead to the formation of more durable, elastic materials. The materials undergo a transformation that changes their physical properties, making them more useful in various applications, including in molds for dental practices or other areas where flexible, yet stable forms are needed.
The vulcanization process notably enhances the properties of elastomers, making them less sticky and more resistant to temperature changes and mechanical stresses. This process involves the addition of sulfur to form cross-links between the polymer chains of the rubber, which are usually in a coiled state, allowing them to stretch and then return to their original positions when the stretching force is removed.