Ionomer Masterbatch Strategy to Enhance Photostability of the Azo Pigment in Polypropylene via Hydrogen‐Bond Networks

ABSTRACT Azo pigments, widely used for their vivid coloration and cost‐effectiveness, have traditionally been susceptible to photochemical degradation upon UV exposure, leading to significant color fading. This study investigated an innovative ionomer masterbatch strategy aimed at enhancing the photostability of azo‐pigmented polypropylene (PP) composites. The approach involved incorporating Surlyn resin (Surlyn 9320) into the composites through masterbatch formulations with benzimidazolone yellow (P.Y.180) pigment. The results showed that this method significantly improved the photostability of the PP composites, with a 52.3% reduction in color difference (Δ E ) after 900 h of UV exposure compared to the unmodified system. Characterization techniques, including FTIR, XPS, SEM, and Raman, revealed the formation of hydrogen bonds between Surlyn 9320 and P.Y.180, which contributed to the improved photostability. Furthermore, the bond dissociation energies were determined by analyzing temperature‐dependent FTIR spectra using the Van't Hoff equation. This hydrogen bonding mainly enhanced the pigment dispersion and interfacial adhesion, synergistically improving the material's photostability and color retention performance. This study provided an effective and economically viable solution for improving the photostability of colored PP materials, with potential applications in various industrial sectors.