How does the thermal degradation temperature of polyethylene limit its applications?

Polyethylene, one of the most widely used plastics, faces significant limitations due to its thermal degradation temperature. Typically, polyethylene begins to degrade at temperatures between 300°C and 350°C, depending on its density and molecular structure. This thermal instability restricts its use in high-temperature environments, such as automotive engine components, industrial machinery, or certain packaging applications where heat resistance is critical.

When exposed to temperatures near its degradation point, polyethylene undergoes chain scission, leading to loss of mechanical strength, discoloration, and the release of volatile compounds. This not only compromises product performance but also raises safety concerns. As a result, industries requiring materials to withstand higher temperatures often opt for more thermally stable polymers like polypropylene or engineering plastics.

Additionally, the recycling process of polyethylene is complicated by its thermal sensitivity, as excessive heat during reprocessing can degrade the material. Understanding these limitations helps engineers and designers select appropriate materials for specific applications, balancing cost, performance, and thermal requirements.