Preparation And Property Research On Super Molecular Structure Of Organic UV Absorbent Intercalated LDHs With Naphthalene Sulfonic Acid

Three organic UV absorbents anions have been intercalated into a layered double hydroxide (LDHs) host by ion-exchange using ZnAl-NO₃-LDHs as precursor with an aqueous solution of 2-naphthylamine-1,5-disulfonic acid (NADA), sodium 2,3-dihydroxynaphthalene-6-sulfonate (DNSA) and disodium 3,6-dihydroxynaphthalene-2,7-disalphonate (DNDA). After intercalation of the UV absorbents, the interlayer distance in the LDHs increases from 0.90 to 1.56 nm for ZnAl-NADA-LDHs, 1.59 nm for ZnAl-DNSA-LDHs and 1.68 nm for ZnAl-DNDA-LDHs. UV-vis test shows good UV absorption capability after intercalated.XRD, FT-IR, TG-DTA and ICP reveal the presence of a complex system of supramolecular host-guest interactions. The thermal stability of the intercalated UV absorbent was investigated by TG-DTA and it was found that this material is more stable than the pure NADA, DNSA and DNDA at high temperature, showing that the thermostability is markedly enhanced after intercalation and the decomposition temperature increased from 350℃to 440℃, 193℃to 445℃and 400℃to 470℃respectively, showing the benefit afforded by intercalation into the LDHs host.The UV absorption capability of LDHs-intercalated UV absorbent NADA was improved greatly in UVA region, the absorptivity near to 90%. The LDHs-intercalated UV absorbent DNSA can absorb more than 85% of the UV-ray in rang of 200-350 nm. The UV absorption capability of ZnAl-DNDA-LDHs was dramatically enhance in entire UV bonds.ZnAl-NADA-LDHs/polypropylene, ZnAl-DNSA-LDHs/polypropylene and ZnAl-DNDA-LDHs/polypropylene composite materials exhibit excellent UV photostability. This shows that the hybrid ZnAl-NADA-LDHs, ZnAl-DNSA-LDHs and ZnAl-DNDA-LDHs phase have potential applications as UV absorbents. The Anti-photodegradation property of polypropylene surface was enhanced by added 1% wt of NADA, DNSA and DNDA intercalated into LDHs.