The Fracture Behavior of Carbon Fibers and Their Effects on Mechanical, Conductive, and Thermal Performance of Carbon Fibers Reinforced PPS / SEBS Blends

ABSTRACT In this work, the fracture behavior of carbon fibers (CFs) with 2 and 10‐mm original lengths in polyphenylene sulfide (PPS)/styrene–ethylene–butylene–styrene (SEBS) blends was investigated. Experimental results found that the residual length of 2 mm of CFs in PPS/SEBS/CF composites was longer at 0.14, 0.17, and 0.22 mm for 15, 20, and 25 wt% of CFs' contents, respectively, while 10 mm of CFs was shorter as 0.11, 0.12, and 0.13 mm for that. The numerical simulation results showed that straight‐rod CFs underwent a bending–folding–breaking–fracture sequential behavior during the mixing process, and the proportion of 2 mm of CFs subjected to total squeezing forces below 10 ⁻⁴ N was around 65%, which was much higher than 6 and 10 mm of original CFs. By constructing CFs' bonding bonds and calculating their retention rate, it was further verified that 2 mm of original CFs was less likely to undergo further bending–folding behavior after experiencing extensive flow field in the initial stages, also making them more stable and retaining a longer residual length in composites. Furthermore, the dimple morphology around CFs and “zig‐zag” fractured surface were observed in the composites prepared by 2 mm of original CFs, also confirming that the formation of a more robust network structure consisting of longer residual CFs and deformed SEBS. This made PPS/SEBS/CF composites show an excellent overall performance with 64.4 J/m of impact strength, 126.7 MPa of tensile strength, 0.01 S/m of electrical conductivity, and 0.65 W/m·K of thermal conductivity.