Co‐ ZIF Modified Boron Nitride Co‐Effecting Ammonium Polyphosphate: A Strategy for Improving the Flame Retardancy and Thermal Conductivity of Polyvinyl Alcohol

ABSTRACT Polyvinyl alcohol (PVA) has superb chemical and physical characteristics, making it important for applications in many areas, but its combustibility limits its broader use. In this work, ZIF‐67@BN, a flame‐retardant and heat‐conducting filler, was synthesized via the in situ growth technique, and its structural and morphological characteristics were studied. ZIF‐67@BN and ammonium polyphosphate (APP) were added to PVA. The findings verify that the LOI value of PVA composites with 1 wt.% of ZIF‐67@BN and 7 wt.% of APP attained 28.1%, which was 36.4% greater than that of pure PVA. In addition, the total heat rate (THR) was 39.0% lower than that of pure PVA, and the peak heat release rate (pHRR) was 61.6% lower. This is because ZIF‐67@BN has a physical barrier effect as a filler and catalyzes the carbonization effect. When heated, APP's decomposition generated non‐flammable gas dilution; at the same time, the production of phosphoric acid and metaphosphoric acid contributed to the dehydration during the carbonization of PVA.