Improving the Ablation and Thermal Protection Performance of Polydimethylsiloxane Composites via Epoxy Modification Through CSi Synergistic Mechanism

ABSTRACT This work develops a series of flexible thermal ablation‐resistant epoxy‐modified polydimethylsiloxane (EDA@PDMS) composites with integrated mechanical and thermal protection performance through multiscale design strategy. EDA@PDMS was prepared by epoxy ring‐opening and hydrosilylation reactions. Then, 10 phr silicon dioxide and 6 phr carbon fibers were added to simultaneously enhance the mechanical strength and ablation resistance of EDA@PDMS‐c. Results showed that the tensile strength of EDA@PDMS‐c reached 2.31 MPa, which is 41.7% higher than that of PDMS‐c. Under 4 MW/m 2 for 30 s, the linear ablation rate (LAR) and mass ablation rate (MAR) of EDA@PDMS‐c reached 0.0515 mm/s and 0.0357 g/s, which were 32.1% and 18.5% lower than those of PDMS‐c, respectively. Additionally, a peak back‐face temperature of 89.4°C was monitored during the ablation process, indicating excellent thermal insulation performance. The above improvement was ascribed to the combined effects of the intrigue molecular structure design through CSi synergistic mechanism and reinforcing fillers. The research proposed a strategy for fabricating high‐performance flexible ablation composites that can be potentially used for thermal protection purposes in the areas of fire protection and aerospace among others.