Radiation-induced degradation in the properties of pristine and double-walled carbon nanotube-enhanced poly(2,5-benzimidazole) polymers for radiation shielding in the LEO

• Enhanced Urbach energy and decreased bandgaps. • Reduced band spectra. • Smoothened surface and amorphisation. Degradation in the properties of polymer-based materials in space environments is a critical challenge for developing lightweight radiation shielding solutions. In this paper, a comparative study of the impacts of helium ion (He + ) irradiation one of the ion species in the Low Earth Orbit (LEO) environment on the structural and optical properties of pristine and 1.0 wt% double-walled carbon nanotube (DWCNT)-enhanced poly(2,5-benzimidazole) (ABPBI) polymers for LEO radiation shielding applications was conducted. The two polymer categories were separately chemically prepared in the laboratory, moulded, dried, and cut into 1 cm × 1 cm pieces, and bombarded with 0.35 MeV He + ions at varying fluences. The Ultraviolet–Visible-Near-Infrared (UV–Vis-NIR) optical analyses of the polymers following the ion bombardment revealed that He + irradiation considerably raises the Urbach energy and decreases the optical bandgap, indicating a rise in electronic defects and structural disorder. On the other hand, the Fourier Transform Infrared (FTIR), Atomic Force Microscopy (AFM), and X-ray Diffraction (XRD) analyses revealed higher levels of structural degradation in the pristine ABPBI samples, suggesting changes brought about by irradiation-induced oxidation and chain scission processes. In contrast, the 1.0 wt% DWCNT-ABPBI composite demonstrated improved optical and structural integrity, retention, and resistance to He + ion-induced damage. According to the results, 1.0 wt% DWCNT reinforcement reduces radiation-induced deterioration and offers more protection from energetic ion exposure in the LEO settings. Thus, this work highlights the distinct impact of He + ion interactions with ABPBI and the effectiveness of DWCNT inclusion in improving polymer resilience, and it contributes to the fundamental understanding of the polymer composite for radiation shielding applications.