Fused Granular Fabrication of <scp>CF</scp> / <scp>PPS</scp> / <scp>PES</scp> Composites: Achieving Superior Interlayer Bonding and Mechanical Strength

ABSTRACT Fused granular fabrication (FGF) of carbon fiber reinforced polyphenylene sulfide (CF/PPS) is often plagued by poor interlayer adhesion, a consequence of the rapid matrix crystallization that restricts polymer chain diffusion. To overcome this critical limitation, a novel strategy was proposed that combines interface regulation with modulation of matrix crystallization kinetics. This is achieved by introducing amorphous polyethersulfone (PES) to adjust the crystallization of PPS, while additionally incorporating a silane coupling agent (KH550) and compatibilizer (SEBS‐g‐MAH) to enhance interfacial interactions. Rheological and thermal analyses confirm that PES effectively retards the crystallization of PPS, thereby creating a wider processing window crucial for intermolecular chain diffusion and interlayer fusion during the FGF process. Consequently, the engineered composites exhibit a well‐balanced combination of mechanical performance, with the tensile and flexural strengths reaching 92.17 and 155.02 MPa, respectively, representing increases of approximately 14% and 6% compared to the unmodified CF/PPS composite (N‐CF). Most notably, the strategy dramatically enhances interlayer bonding, evidenced by a Z ‐direction tensile strength of 29.04 MPa and significantly reduced porosity. This work demonstrates that a dual approach of managing crystallization kinetics while reinforcing the interfacial architecture is paramount for FGF of high‐performance thermoplastic composites. The findings offer not only a viable material solution but also fundamental mechanistic insights for advancing pellet‐based additive manufacturing.