Effect of Multi‐Walled Carbon Nanotubes on the Properties of <scp>EPDM</scp> Composites Reinforced With Polyimide Short Fibers Prepared by Solution Wet Mixing

ABSTRACT To investigate the effect of solution‐based wet mixing on the properties of multi‐walled carbon nanotube/polyimide short fiber/EPDM (MWCNTS/PISF/EPDM) composites, MWCNTS were incorporated into the composites using both dry and solution‐based wet mixing processes. Experimental results show that under the same mixing method, the addition of MWCNTS improves the 100% modulus and enhances the ablation resistance of the EPDM composites. The solution‐based wet mixing process further improves the dispersion and distribution of both PISF and MWCNTS within the EPDM matrix. Uniformly dispersed short fibers and MWCNTS form a hierarchical filler network, which reduces the Payne effect and enhances mechanical properties. Compared to GC6, the SC6 sample shows a 59.16% increase in tensile strength and a 98.01% increase in elongation at break, along with a notable improvement in 100% modulus. Furthermore, the hierarchical filler network formed by the fibers and MWCNTS during ablation creates a dense supporting skeleton. The linear ablation rate of SC6 reaches 0.037 mm/s, which is 17.78% lower than that of GC6, and its carbonized layer is significantly denser. Therefore, the solution‐based wet mixing process effectively improves both the mechanical and ablation resistance properties of MWCNTS/PISF/EPDM composites, providing a novel processing strategy for the fabrication of high‐performance ablation‐resistant rubber‐based insulation layers.