Polyimide Microwave Absorption Foam Reinforced With Epoxy Resin and Integrated With Multifunctionality.

Area of Science:

• Materials Science
• Polymer Chemistry
• Aerospace Engineering

Background:

• Polyimide (PI) microwave absorption (MA) foam is valuable in aerospace for its lightweight and stability.
• Poor mechanical properties and processing limitations hinder broader PI MA foam applications.
• Improving intrinsic mechanical properties of PI MA foam is a significant challenge.

Purpose of the Study:

• To enhance the mechanical properties of PI MA foam.
• To develop a straightforward and industrial-scale strategy for multifunctional PI MA foam.
• To create PI MA foam suitable for electromagnetic/infrared stealth in harsh environments.

Main Methods:

• In situ foaming process with epoxy group grafting onto PI main chain.
• Incorporation of rigid segments to form a cross-linked, interpenetrated, and entangled network.
• Molecular design for enhanced polarity and stiffness, and component regulation for optimized skeletal structure.

Main Results:

• Achieved superior mechanical strength and structural stability up to 200°C and 10,000 times self-weight load.
• Obtained optimal effective absorption bandwidth (EAB) of 10.5 GHz at 1.5 wt.% CNT content and 2.5 mm thickness.
• Demonstrated multifunctional PI MA foam suitable for electromagnetic/infrared stealth.

Conclusions:

• The developed PI MA foam exhibits excellent mechanical and thermal properties.
• The in situ foaming strategy offers an industrial-scale approach for advanced PI MA foam.
• The material is promising for electromagnetic/infrared stealth applications in demanding aerospace conditions.