Phytic acid-metal ion chelate coated layered clay and its enhancement and antibacterial effect in poly (<i>ε</i>-caprolactone)

Abstract

Based on the excellent chelating ability of phytic acid (PA), Ag+, Cu2+, Fe3+, and Zn2+, were used to chelate with PA, and deposited on the surface of layered double hydroxides (LDHs) to form core-shell structure, so as to improve the interfacial compatibility between layered clay and polymer matrix. Surface coated LDHs (LDHs@PA-M) loaded with different metal ions were prepared. The micromorphology of LDHs@PA-M loaded with different metal ions was studied and applied in the strengthening modification of poly(ε-caprolactone) (PCL). The results show that PA can form stable and uniform nano-coatings with Ag+ and Cu2+on the surface of LDHs. With the excellent antibacterial activity of Ag+ and Cu2+, the antibacterial rates of LDHs@PA-Ag+ and LDHs@PA-Cu2+ against Escherichia coli (E.coli) both exceed 99.99%. Compared with pure PCL, the tensile strength and elongation at break of LDHs@PA-Cu2+/PCL nanocomposites (mass fraction of LDHs@PA-Cu2+ is 1%) increase by 30.7% and 33.3%, reaching 40.9 MPa and 816%, respectively. The enhancement of mechanical properties for LDHs@PA-Cu2+/PCL nanocomposites is the most remarkable. The antibacterial rate of LDHs@PA-Cu2+/PCL and LDHs@PA-Ag+/PCL nanocom-posites against E.coli both exceed 99.99%. It shows excellent antibacterial activity, which expands the application of layered clay/bio-based polymer nanocomposites in the field of active packaging.

Keywords

• phytic acid
• layered clay
• surface modification
• interfacial compatibility
• antibacterial activity