Simultaneously Improving Thermal Insulation, Flame Retardancy, and Smoke Suppression for Rigid Cross-Linked Polyvinyl Chloride Foam through Combined Copper/Molybdenum Trioxide

Although the rigid cross-linked polyvinyl chloride (c-PVC) foam has excellent mechanical properties, there are still problems of unsatisfactory thermal insulation performance, flame retardancy, and smoke suppression. So how to simultaneously improve the thermal insulation and flame retardant properties of c-PVC foam is still a challenge. Herein, the combination of copper powder and molybdenum trioxide (Cu/MoO 3 ) is used to prepare c-PVC composite foams. The cell structure, thermal conductivity, thermal stability, limiting oxygen index (LOI), and smoke density of the c-PVC composite foams are characterized. The results showed that, on the one hand, the cell density and thermal insulation performance are improved (31.24 mW m −1 K −1 ) due to the good heterogeneous nucleation and infrared reflection of the copper powder. On the other hand, when the mass ratio of Cu/MoO 3 is 4/1, the best synergistic catalytic effect to promote char formation achieved the highest LOI value of 30.1, and the smoke density rating (SDR) is reduced by 27%. This work is beneficial to the design and application of c-PVC foams with high performance.