Preparation of CaMgAl‐LDHs and Its Effect on Flame Retardant and Smoke Inhibition of PVC

To effectively enhance the flame retardant and smoke suppression performance of PVC materials, this study successfully synthesized calcium‐magnesium‐aluminum hydrotalcite using the urea decomposition‐hydrothermal method. The optimal crystallinity of the CaMgAl‐LDHs was achieved at a molar ratio of CaMgAl of 1:2:1, with a crystallization temperature of 120°C, a crystallization duration of 18 h and a urea dosage of 0.010 moles. The results indicated that the elongation at break decreased by 27.13% and the tensile strength reduced by approximately 33.2% compared to pure PVC, although the mechanical properties of the composite film slightly decreased, more importantly, its flame retardant, smoke suppression performance, and thermal stability were improved. This improvement was evidenced by a 40% extension in the initial thermal degradation time and a 63.49% reduction in the maximum specific optical density. The heat release rate (HRR), total heat release (THR), smoke production rate (SPR), and total smoke production (TSP) of the composite membrane were decreased by 8.5%, 20.72%, 34.07%, and 33.93%, respectively. The LOI increased to 25.5%, reaching the HB grade. This research not only offers novel insights for the development of high‐efficiency flame retardant but also establishes a crucial theoretical foundation for the safe application of PVC membrane materials.