Construction of hydrophobic core-shell flame retardant: A novel strategy towards reducing fire hazards and reinforcing mechanical properties of polypropylene.

In order to expand the application of polypropylene (PP) in the field of systems and overcome the shortcomings of layered double hydroxide (LDH) in flame retardancy and smoke suppression, a novel organic and inorganic hybrid core-shell type flame retardant was designed and prepared in this work. The flame retardant took LDH as the core, intumescent flame-retardant (IFR) generated by the condensation reaction of tannic acid (TA) and cyanuric chloride (CC) as the shell layer to construct the core-shell structure, and used the property of TA chelating Fe to integrate several flame-retardant materials (LDH@TA-CC-Fe). It was worth noting that the PP/20%LDH@TA-CC-Fe composites could pass the vertical combustion rating (UL-94) V0 rating and achieve a limit oxygen index (LOI) of 30.2% after adding 20 wt% LDH@TA-CC-Fe. Compared with Neat PP, peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) of PP/20%LDH@TA-CC-Fe composites were reduced by 45.9%, 50.3%, and 36.5%, respectively. [Display omitted] • The hydrophobic core-shell flame retardant LDH@TA-CC-Fe hybrids was synthesized successfully. • The LOI value of PP/20%LDH@TA-CC-Fe is 30.2%, and the UL-94 grade reaches V0 rating. • PP/20%LDH@TA-CC-Fe exhibited low-value of HRR, THR, and TSP, which are 432.82 kW∙m−2, 38.35 MJ∙m−2, 10.12m2. • The reinforcements attributed to the cooperative effect between LDH and IFR. [ABSTRACT FROM AUTHOR]