Zn2Al Layered Double Hydroxides Intercalated with Nitrate and p-Aminobenzoate as Ultraviolet Protective Agents in Low-Density Polyethylene Nanocomposites and Natural Insulating Oils

Abstract

Zn 2 Al-Cl and Zn 2 Al-NO 3 layered double hydroxides (LDHs) were synthesized through the fixed pH co-precipitation method and used as precursor materials for the intercalation of p-aminobenzoate through anion exchange reactions. Since chloride in Zn 2 Al-Cl was only partially exchanged with p-aminobenzoate, the phases Zn 2 Al-NO 3 and Zn 2 Al-NAB (nitrate exchanged with p-aminobenzoate) were used in different percentages as functional fillers to produce nanocomposites of low-density polyethylene doped with maleic anhydride (LDPE). Analysis of thermal properties showed that the melting and recrystallization temperatures were slightly increased in the nanocomposite containing 5 wt.% Zn 2 Al-NAB. Weathering tests performed with neat LDPE and the nanocomposite films showed that the addition of the LDHs improved ultraviolet (UV) absorption and reduced the LDPE degradation by 25 and 76% when using Zn 2 Al-NO 3 and Zn 2 Al-NAB , respectively, as fillers, showing a promising UV-shielding effect. Preliminary results also showed a potential application of Zn 2 Al-NAB as antioxidant in natural insulating oils (natural ester FR3 and castor oil), opening new opportunity of applications.