Rubber-iron interface separation using liquid nitrogen for material selective recycling and its mechanism.

Area of Science:

• Materials Science
• Mechanical Engineering

Background:

• Rubber-metal composites offer valuable properties like impact resistance and vibration damping.
• Efficient separation of these composites is crucial for recycling and environmental management.
• Current separation technologies are limited by strong bonding and thermal/mechanical process constraints.

Purpose of the Study:

• To investigate cryogenic cooling as a novel interface separation method for rubber-metal composites.
• To elucidate the underlying mechanism of cryogenic separation.
• To assess the influence of material properties and geometry on the separation process.

Main Methods:

• Immersion of rubber-metal composite specimens in liquid nitrogen (77.15 K).
• Observation of interfacial separation behavior and residual rubber patterns.
• Thermal stress simulations to analyze elastic strain energy concentration at interfaces.

Main Results:

• Interfacial separation was achieved after approximately 60 seconds of liquid nitrogen immersion.
• Separation initiates via crack propagation near interface corners post-rubber glass transition.
• Separation effectiveness is influenced by rubber layer thickness/geometry and metal's Young's modulus.

Conclusions:

• Cryogenic cooling presents a viable, non-heating method for separating rubber-metal composites.
• The mechanism involves thermal stress-induced crack propagation.
• Optimizing geometry and material selection can enhance cryogenic separation efficiency.