Dual‐exterior surface modification of layered double hydroxides and its application in flame retardant biobased poly(trimethylene terephthalate)

Abstract

The overall target of this research was to design a dual‐exterior surface chemical modification of eco‐friendly layered double hydroxides (LDH‐S@PA) using calcium stearate and phytic acid (PA) containing‐rich phosphorus to synchronously boost the dispersibility in the polymer matrix and the flame retardancy. Microstructure, surface chemical environments and morphologies of LDH‐S@PA were characterized. It was found that the target product with the hydrophobic surface was successfully prepared. The basic morphologies of LDH‐S@PA exhibited thin flat crystals composed of multi‐sheet with hexagonally arranged spots. Meanwhile, the thermal stability of LDH‐S@PA was improved. Significantly, after adding LDH‐S@PA into biobased poly(trimethylene terephthalate) (PTT) via melting‐blending, LDH‐S@PA exhibited a higher dispersity in the PTT matrix and the PTT/LDH‐S@PA composite with 20 wt% loading achieved 29.8% limiting oxygen index value and possessed V‐0 rating in UL‐94 test, revealing LDH‐S@PA dramatically enhanced the flame retardancy of the PTT. The flame retarded mechanism of LDH‐S@PA in PTT was discussed based on gaseous and condensed phase analysis. In addition, the incorporation of LDH‐S@PA improved the mechanical properties of the composites. This facile and straightforward approach for dual‐surface modification LDHs holds promise as flame retardant formulations for polymer in future applications.

Study on the Flammability, Crystal Behaviors and Mechanical Performance of Polyamide 11 Composites by Intercalated Layered Double Hydroxides

“…Layered double hydroxides (LDH) have shown good flame retardancy and smoke suppression with nontoxic and halogen-free properties due to their unique chemical composition and layered structure [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. For the special layered structure with exchangeable anion between layers, some researchers have attempted to intercalate flame-retardant elements to enhance its efficiency [ 19 , 20 ].…”