How does the resistance to hydrolysis of polyethylene compare to PVC in wet environments?

The resistance to hydrolysis of polyethylene (PE) and polyvinyl chloride (PVC) in wet environments varies significantly due to their distinct chemical structures. Polyethylene, a non-polar hydrocarbon polymer, exhibits excellent resistance to hydrolysis because it lacks functional groups that react with water. This makes PE highly durable in moist or submerged conditions, such as in marine applications or water pipes.

In contrast, PVC contains polar carbon-chlorine bonds, which are more susceptible to hydrolysis, especially at elevated temperatures or in acidic/alkaline environments. Over time, PVC may degrade as these bonds break, releasing hydrochloric acid and weakening the material. However, additives like stabilizers can improve PVC's hydrolysis resistance for specific applications.

Overall, polyethylene outperforms PVC in long-term wet environments due to its inherent stability, while PVC requires additional modifications to enhance its durability against hydrolysis. The choice between the two depends on the specific conditions and required lifespan of the material.