Phthalocyanine-terminated poly(aryl ether) sizing: An efficient strategy in interfacial interactions optimization of CF/PPESK composites with excellent thermal-resistant

To ameliorate the poor interfacial adhesion between high performance polymer and carbon fiber (CF), A series of cyano-terminated poly(phthalazinone ether nitrile/sulfone/ketone)s (PPEN/S/K-CN) and phthalocyanine-terminated poly(phthalazinone ether nitrile/sulfone/ketone)s (PPEN/S/K-Pc) with excellent thermal stability were synthesized to sizing CF with a simple dip coating approach. The application of these sizing agents with structural similarities to the matrix, yielded enhancements in both interface quality and mechanical properties within CF/PPESK composites, which facilitated by the mechanisms of mechanical interlocking and entanglement in the interface. Among them, PPEN-Pc@CF/PPESK demonstrated superior ILSS at 81.8 ± 1.3 MPa and flexural strength at 1470 ± 15 MPa, which were increased by 32% and 44% compared to CF-desized/PPESK, respectively. Notably, The efficacy of the phthalocyanine-terminated poly(aryl ether) sizing agents in enhancing IFSS and ILSS surpassed that of cyano-terminated counterparts. This disparity was primarily attributed to the robust π-π interaction facilitated by the conjugated cyclic phthalocyanine structure, enhancing adhesion between the sizing agents and the CF surface. Molecular dynamics (MD) simulations substantiated this interaction. And SEM cross-sectional analysis of the composites provided visual confirmation of the reinforced interface. In brief, the strategic design and implementation of phthalocyanine-terminated high-performance thermoplastic sizing agents, offer a novel ideal for the development of advanced CF-reinforced polymer composites.