Synthesis of Poly(bisphthalazinone sulfone ketone)s for Long-Term Use above 300 °C with Excellent Environmental Aging Resistance, Solvent Recyclability, and Intrinsic Flame Retardancy

High Resolution Image Download MS PowerPoint Slide This study synthesized 4,4′-(sulfonylbis(4,1-phenylene))bis(phthalazin-1(2H)-one) via an efficient three-step method and subsequently prepared amorphous poly(sulfone-type bisphthalazinone sulfone ketone)s (PSUPSKs). PSUPSKs exhibit glass transition temperatures ranging from 346 to 372 °C, with a 5% weight loss temperature exceeding 500 °C. PSUPSKs possess excellent solubility and can be solution-processed into cast films, electrospun nanofibers, and coatings. PSUPSK sheets exhibit superior mechanical properties and excellent high- and low-temperature resistance at 300 and −60 °C, respectively. Additionally, these materials show excellent thermal and environmental aging properties at 300 °C, as well as inherent flame retardancy with a UL-94 V-0 rating. Solution-impregnated CF/PSUPSK composites demonstrate exceptional mechanical performance, with flexural strengths of 1368–1510 MPa, while retaining 64.8–81.4% of their flexural strength at 300 °C and 19.1–54.3% at 330 °C. Moreover, the composites enable efficient carbon fiber recovery and resin recycling via mild solvent dissolution. PSUPSKs show great potential for 5G substrates, new energy vehicles, and aerospace applications.