▎ 摘　　要

Many advanced fillers were used in ethylene propylene diene monomer (EPDM) insulation composites to enhance the ablative resistance by strengthening char layer. However, the structures of fillers and char layer were usually neglected. In this work, a new type of cross-linked network-like polyphosphazene nanotubes (PNTs) was added in EPDM composites in combination with graphene. The results showed that the ablation performance of EPDM composites was improved by 21.6% with the synergistic effect of PNTs and graphene. Moreover, the ablation mechanism was studied by analyzing ablated char layer using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy disperse spectroscopy (EDS) and Raman spectroscopy. PNTs served as skeleton to build the cross-linked network char layer and graphene played a role in enhancing the properties of char layer. The findings of this work emphasize the synergistic effect of structures and properties of fillers when performing ablative modification, which provides a new idea to enhance the ablation properties of EPDM composites.