Synthesis and UV absorption properties of 5, 5′-thiodisalicylic acid intercalated Zn−Al layered double hydroxides

Abstract

5, 5′-Thiodisalicylic acid (TDSA) has been intercalated into a ZnAl–NO 3 layered double hydroxide (LDH) by an ion-exchange reaction. After intercalation of TDSA, the basal spacing in the LDH increased from 0.89 to 1.53 nm, suggesting that the TDSA anions were arranged in the interlayer galleries of ZnAl–TDSA–LDH as a tilted monolayer arrangement of dianions. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TGA–DTA), and UV–Visible spectroscopy (UV–Vis). The results show that the NO 3 − anions in the precursor have been completely replaced by TDSA anions to give ZnAl–TDSA–LDH having crystalline-layered structure. Detailed studies reveal the presence of a complex system of supramolecular interactions between LDH layers and TDSA anions. TGA–DTA curves suggest that the thermostability of TDSA was markedly enhanced by intercalation in the LDH host. Photostability tests show that the film of ZnAl–TDSA–LDH/PP possessed higher stability to UV radiation than either the film of TDSA/PP or pristine PP.