Degradation

Degradation of a plastic material can occur as a result of reduction in molecular weight, separation of the polymer and its additives, damage to the additives, or a chemical reaction. Conditions leading to material degradation during injection molding can include: too high of a melt temperature, long residence times, excessive shear rates and frictional heating in a runner, poor venting, and dead or low flow areas in the injection barrel or hot runner system. Additionally, some materials can degrade as a result of improper drying. For example, drying a material at too high of a temperature for too long can create oxidation. Additionally, injection molding certain materials with too much moisture, such as Nylon, PC and polyurethanes can cause the material to undergo hydrolysis.

 

ChainDegradationShearDegradation

 

 

 

WE'RE HIRING! AIM is hiring an Injection Molding Process Instructor  Learn More