Meaning
Self-accelerating temperature increases driven by exothermic chemical reactions represent a catastrophic failure mode in the processing of thick polymeric structures. A thermal runaway occurs when the heat generated by the curing resin exceeds the heat dissipated by the mold and surrounding environment. This self-sustaining cycle leads to rapidly increasing reaction rates and extreme internal temperatures.
Chemical Acceleration
Thermosetting resins release heat as they cure, and the reaction rate is highly temperature dependent. When the temperature rises, the reaction accelerates and releases more heat. This feedback loop is particularly dangerous in thick laminates where the polymer acts as an thermal insulator.
Material Destruction
The extreme temperatures reached during such an uncontrolled event can exceed the degradation point of the polymer. This overheating causes matrix cracking, smoking, and potentially fire within the cure chamber. Parts affected by such events must be scrapped immediately because their mechanical properties are ruined.
Thermal Intervention
Manufacturing procedures include specific cooling cycles or emergency tool venting to prevent this hazard. Engineers use simulation models to determine the maximum thickness that can be cured safely under standard conditions. Demonstrating safe processing of these limits is required before transitioning from prototype to full-scale production runs.
