Heterogeneous Waterborne Polyurethane Composite with Alternating Electromagnetic Layers for Absorption-Dominated...

Area of Science:

• Materials Science
• Polymer Science
• Electromagnetics

Background:

• Electromagnetic interference (EMI) shielding is crucial for advanced electronic devices.
• Flexible and high-performance EMI shielding materials are in high demand.
• Existing materials often face limitations in flexibility, effectiveness, or durability.

Purpose of the Study:

• To fabricate flexible waterborne polyurethane (WPU) composites for EMI shielding.
• To investigate the impact of a heterogeneous alternating multilayer structure with a conductive gradient.
• To achieve absorption-dominated EMI shielding with high effectiveness and stability.

Main Methods:

• Layer-by-layer stacking and hot-pressing techniques were employed.
• Incorporation of metallized chopped polyimide fiber (PI@Ni/Cu/Ni), reduced graphene oxide (rGO), and Fe3O4 fillers.
• Design of multilevel electromagnetic wave propagation paths for enhanced loss mechanisms.

Main Results:

• The developed WPU composite achieved a high EMI shielding effectiveness (SE) of 53.90 dB.
• An absorption value (A) of 0.56 was recorded, indicating absorption-dominated shielding.
• The material demonstrated excellent integrity under bending, soaking, and burning tests.

Conclusions:

• A viable strategy for designing absorption-dominated EMI shielding materials was presented.
• The multilayer WPU composite offers controllable and stable performance.
• The material is suitable for next-generation advanced electronic products requiring robust EMI protection.