A smartDOPO‐containing decoration armed on Salen‐polyphosphazene toward high‐efficient flame retardancy for epoxy thermoset

Abstract Use of Salen‐phosphazene (Salen‐PZN) complex for flame retardant polymeric materials demonstrate good flame retardancy due to their abundant flame retardant elements and aromatic‐rich structure. To further enhance their flame retardancy and interaction with the matrix, phosphorous (DK) was armed on nickel‐based Salen‐polyphosphazene complex (DK@Salen‐PZN‐Ni) as a smart decoration. The composite with DK decoration has higher tensile strength than the DK‐free composite. Moreover, cone calorimeter study showed that with 3 wt% total additive loading, the peak heat release rate (pHRR) and peak smoke rate (pSPR) of DK@Salen‐PZN‐Ni/EP composite were reduced by 21.0% and 30.3%, respectively when compared with pure EP. The limited oxygen index of the composite was 30.2%, while the vertical burning test (UL‐94) reached the V‐1 rate. Flame retardance mechanism of DK@Salen‐PZN‐Ni was discussed in detail. The designing of flame retardants alleviated the mechanical property failure and improved the flame retardancy of polymeric composite.