Comparative analysis of single-walled, double-walled, and multi-walled carbon nanotube-reinforced Poly(2,5-benzimidazole) composites: Enhanced structural and thermal stability for radiation shielding in low Earth Orbit

Poly(2,5-benzimidazole) (ABPBI) composites reinforced with 1 wt% single-wall (SWCNT), double-wall (DWCNT), and multi-wall (MWCNT) carbon nanotubes were synthesized and evaluated for radiation shielding applications in Low Earth Orbit (LEO). The structural and thermal properties of these nanocomposites were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Atomic Force Microscopy (AFM). FTIR analysis confirmed the retention of ABPBI’s characteristic molecular structure across all nanocomposites, with ABPBI/DWCNT exhibiting the strongest molecular bonding. Thermal analysis demonstrated exceptional stability, with ∼95% weight retention at 400°C and ∼70% at 900°C, suggesting suitability for high-temperature applications. To assess radiation resistance, 3 MeV He 2+ ion bombardment was performed on ABPBI/DWCNT nanocomposites. Post-irradiation FTIR and XRD results indicated mild molecular degradation but preserved semi-crystalline structures, demonstrating strong radiation tolerance. AFM analysis further revealed nanoscale surface modifications, providing insights into radiation-induced morphological changes and confirming the structural resilience of ABPBI-based nanocomposites. The results suggest that ABPBI/DWCNT exhibits promising mechanical integrity, thermal stability, and radiation resistance for space applications. • Enhanced radiation shielding properties: The ABPBI nanocomposites reinforced with single-walled (SWCNT), double-walled (DWCNT), and multi-walled carbon nanotubes (MWCNT) exhibit superior resistance to radiation-induced degradation, making them ideal for Low Earth Orbit (LEO) applications. • Exceptional thermal stability: All nanocomposites demonstrate high thermal resistance, with weight retention exceeding 95% at 100°C and 70% at 900°C, ensuring reliability in extreme space temperatures. • Optimized mechanical and molecular interactions: The addition of DWCNT provides the strongest molecular bonding with ABPBI, resulting in improved structural integrity and long-term durability under harsh conditions. • Lightweight and multifunctional: The composites maintain low density while combining high strength, thermal stability, and radiation resistance, making them suitable for shielding, structural components, and spacecraft coatings. • Broad aerospace applicability: These materials offer significant advantages over conventional metal and polymer-based shielding materials due to their reduced secondary radiation effects, processability, and lightweight nature.