Fabrication and characterization of shape memory polyurethane/GNP/MWCNTs nanocomposite thin-films with enhanced UV resistance

Polymer films provide multifunctional platforms for diverse technological applications such as protective coatings, miniaturized sensors, biomedical devices, and energy storage systems. Shape memory polyurethane (SMPU) is a smart polymer capable of responding to external stimuli; however, its moderate mechanical strength and limited shape recovery efficiency restrict broader utilization. In this study, SMPU thin-films were independently reinforced with 1 wt% graphene nanoplatelets (GNPs) and multi-walled carbon nanotubes (MWCNTs) using the solvent-casting method. The resulting nanocomposite thin-films were comprehensively characterized to evaluate their thermal stability, mechanical performance, structural features, and shape recovery behavior, as well as the influence of nanofillers on their UV resistance under accelerated irradiation. The incorporation of GNPs and MWCNTs markedly enhanced the mechanical, thermal, shape recovery, and UV-resistant properties of SMPU. After 24 h of UV irradiation, tensile strength increased by 69% in GNP-reinforced and 72% in MWCNT reinforced thin-films. Notably, the shape recovery rate accelerated by 10–20%. Moreover, owing to the superior UV absorption and radical-scavenging abilities of both nanofillers, the nanocomposite thin-films exhibited lower photooxidative index values compared to pure SMPU. Hence, the findings of this study contribute to the development of high-performance SMPU-based nanocomposites for various potential applications.