Interfacial Separation of Insert Injection-Molded PS/Al Joints Induced by a UV/Heat-Activated Foaming Polymer

Area of Science:

• Materials Science
• Polymer Chemistry
• Surface Engineering

Background:

• Developing controllable polymer-metal interfaces is crucial for advanced manufacturing.
• Current methods for separating bonded materials often lack precision or require harsh conditions.

Purpose of the Study:

• To investigate a thermoacid-triggered delamination system for polystyrene/aluminum (PS/Al) joints.
• To demonstrate precise control over the separation of PS/Al insert injection-molded joints.

Main Methods:

• Utilized poly(tert-butoxycarbonyl styrene) [p(t-BocSt)] as a thermoacid-triggered delamination layer.
• Employed a double-unlocking mechanism involving UV light irradiation and thermal treatment.
• Analyzed interface morphology using microscopy and assessed joint strength via tensile shear testing.

Main Results:

• Achieved uniform interfaces before activation; post-activation showed pore formation and delamination due to gas release (CO2, isobutene).
• PS/Al joint strength was initially ~326 N, decreasing by up to 84% after the foaming process.
• Demonstrated precise control over interfacial weakening and separation through the activation sequence.

Conclusions:

• The p(t-BocSt) system offers a controllable and separable polymer-metal bonding platform.
• The proposed system allows for tunable delamination of PS/Al joints via a UV/thermal activation sequence.