What is the purpose of inhibitors in polymerizable materials?

• A. To speed up polymerization to finish quickly.
• B. To slow or prevent polymerization and prevent runaway.
• C. To change color of material.
• D. To catalyze decomposition.

Answer: (B)

Inhibitors are radical scavengers added to polymerizable materials to control when the reaction starts. They neutralize or trap the free radicals that would initiate polymerization, which keeps the material from curing during storage or handling. This extends shelf life and helps prevent runaway polymerization that could release heat too quickly or cause other safety issues when the material is later mixed or heated.

They aren’t meant to speed up curing; that would be the job of initiators or catalysts. They also don’t inherently change color or catalyze decomposition—in fact, they act to slow or prevent the process until you’re ready to cure. When you want curing to proceed, you use conditions (like heat or light or a stronger initiator) that overwhelm or bypass the inhibitor.