Study on the Thermal Stabilization Behavior, Hydrophilicity, and Rheological Properties of Poly(Acrylonitrile‐Acrylamide‐Monobutyl Itaconate) Terpolymers as Carbon Fiber Precursor

ABSTRACT The thermal oxidative stabilization process of polyacrylonitrile (PAN) is a critical stage that significantly determines the quality of the final carbon fibers. The hydrophilicity and rheological properties of polymers have a profound influence on the compactness of precursor fibers. In this study, acrylamide (AM) and monobutyl itaconate (MBI) were selected as comonomers, and P(AN‐MBI) and P(AN‐MBI‐AM) were synthesized via aqueous‐phase free‐radical polymerization. The structural evolution, thermal behavior, thermal stability, hydrophilicity, and rheological properties of the polymers were systematically analyzed. FTIR and XRD results indicated that the stabilization reaction was promoted by the incorporation of MBI and AM monomers. The thermal behavior and stability under different atmospheric conditions were investigated using DSC and TGA, and the potential synergistic effects of comonomers and oxygen on structural evolution were discussed. Static contact angle measurements revealed that MBI had a relatively minor effect on enhancing the hydrophilicity of polymer films, whereas the introduction of AM significantly improved hydrophilicity. Rheological analysis was conducted to explore the influence of MBI and AM monomers on the rheological properties of PAN polymer solutions, providing insights into the spinning process and optimizing spinning parameters.