Which curing mechanism involves moisture from the air diffusing into the adhesive, causing it to cure from the outside toward the center?

• A. Conventional Cure (Moisture Cure)
• B. Bond
• C. Cross-linked
• D. Compliance Violation

Answer: (A)

Moisture-curing adhesives rely on water from the surrounding air to drive the cure. In this mechanism, humidity diffuses into the adhesive starting at the outer surface, so the chemical reaction begins there and progresses inward as more moisture penetrates. That creates a curing front that moves from the outside toward the center, which is exactly what happens when the adhesive cures from exposure to ambient air.

This fits the scenario of an adhesive that uses atmospheric moisture to cure, as opposed to a mechanism that would describe the bond itself, or the polymer network structure (cross-linked) without specifying how curing starts, or something unrelated like a compliance issue.