Atomic-Oxygen-Durable and Electrically-Conductive CNT-POSS-Polyimide Flexible Films for Space Applications

Area of Science:

• Materials Science
• Aerospace Engineering
• Polymer Chemistry

Background:

• Polymeric materials like polyimide (PI) Kapton degrade in low Earth orbit (LEO) due to atomic oxygen (AO) and electrostatic discharge (ESD).
• Existing methods for incorporating additives like carbon nanotubes (CNTs) often lead to agglomeration and property degradation.

Purpose of the Study:

• To develop PI-based nanocomposite films with improved AO durability and ESD protection.
• To investigate the effect of polyhedral oligomeric silsesquioxane (POSS) content on the properties of CNT-PI nanocomposites.
• To introduce a novel method for preparing these nanocomposites that prevents CNT agglomeration.

Main Methods:

• Preparation of PI-based nanocomposite films incorporating POSS and CNT additives using a unique method.
• Characterization of electrical, mechanical, and thermo-optical properties of the developed films.
• Exposure of films to AO and assessment of their resistivity and erosion yield.
• Testing of film durability through rolling and exposure to thermal cycling and ionizing radiation.

Main Results:

• CNT-POSS-PI films with 5 and 15 wt% POSS showed low sheet resistivities (as low as 200 Ω/□) that remained stable after AO exposure.
• The erosion yield of CNT-POSS-PI films (15 wt% POSS) was approximately one order of magnitude lower than pure PI films under AO fluence.
• The conductivity of the composite films demonstrated excellent durability, withstanding repeated rolling and showing stability to thermal cycling and radiation.

Conclusions:

• The developed CNT-POSS-PI nanocomposite films exhibit superior AO durability and ESD protection compared to pure PI.
• The films maintain electrical conductivity and mechanical integrity under harsh space environmental conditions.
• These nanocomposite films are highly suitable for LEO applications requiring flexible, thermally stable, conductive, and AO-resistant materials, such as spacecraft thermal blankets.