Thermal Degradation Mechanism and Countermeasures

Thermal degradation refers to a phenomenon in which molecular chain scission occurs due to thermal energy and the influence of trace resisuals of oxygen dissolved in the molten resin. As a result, it can cause reduced strength (brittleness), resin discoloration, and molding defects due to gas generation.

Because thermal degradation is influenced by both temperature and time, it is more likely to occur when molding is performed at unnecessarily high temperatures or when the resin remains in the molding machine for an extended period of time.
The degradation mechanism depends on the polymer structure; in some cases, radicals are generated within the system and oxidizable regions undergo changes, while in other cases, bond rearrangement occurs between adjacent bonds, leading to main-chain scission.

※This article is written with the use of Iupizeta EP in mind and does not apply to all plastics.