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

Abstract

In low Earth orbit (LEO), hazards such as atomic oxygen (AO) or electrostatic discharge (ESD) degrade polymeric materials, specifically, the extensively used polyimide (PI) Kapton. We prepared PI-based nanocomposite films that show both AO durability and ESD protection by incorporating polyhedral oligomeric silsesquioxane (POSS) and carbon nanotube (CNT) additives. The unique methods that are reported prevent CNT agglomeration and degradation of the CNT properties that are common in dispersion-based processes. The influence of the POSS content on the electrical, mechanical, and thermo-optical properties of the CNT-POSS-PI films was investigated and compared to those of control PI and CNT-PI films. CNT-POSS-PI films with 5 and 15 wt % POSS content exhibited sheet resistivities as low as 200 Ω/□, and these resistivities remained essentially unchanged after exposure to AO with a fluence of ∼2.3 × 10(20) O atoms cm(-2). CNT-POSS-PI films with 15 wt % POSS content exhibited an erosion yield of 4.8 × 10(-25) cm(3) O atom(-1) under 2.3 × 10(20) O atoms cm(-2) AO fluence, roughly one order of magnitude lower than that of pure PI films. The durability of the conductivity of the composite films was demonstrated by rolling film samples with a tight radius up to 300 times. The stability of the films to thermal cycling and ionizing radiation was also demonstrated. These properties make the prepared CNT-POSS-PI films with 15 wt % POSS content excellent candidates for applications where AO durability and electrical conductivity are required for flexible and thermally stable materials. Hence, they are suggested here for LEO applications such as the outer layers of spacecraft thermal blankets.

Tribological properties of the polyacrylate/PTFE coating modified by POSS in the space environment

“…However, the Si 2p peaks for the coatings exposed to AO shifted to higher binding energies from 102.4 to 103.3 eV compared to unexposed coatings, indicating the oxidation of silicon from Si 2 O 3 to SiO 2. These changes are consistent with the observations from SEM, FTIR, and XRD and confirm that the incorporation of OvPOSS improves the AO resistance of the PMB/PTFE composite coatings.…”

3D Graphene-Infused Polyimide with Enhanced Electrothermal Performance for Long-Term Flexible Space Applications

“…The composite films demonstrated an increase in α s by a factor of 2 compared to that of pure PI (i.e., Kapton). This phenomenon is well known from previously studied carbon‐based composites for space applications …”

Modern Approaches to Polymer Materials Protecting from Ionizing Radiation

“…Relatively small amount of nanofiller is enough for improving properties of CNT-based polymer composites, which are featured by exceptionally high values of elastic modulus and tensile strength (of up to 1 TPa and tens or hundreds GPa respectively), and also thermal and electrical conductivity and high in-air oxidation resistance (>700 o C), without losing their elasticity 44,47,48 . Micro-and nanomaterials scattered in polymer matrix can be used for developing effective radiation protection, including their application as an alternative to metal structural materials 49,50 .…”