Rheological Properties Of Poly (Acrylonitrile-co-itaconic Acid)/DMSO Solutions

PAN-based carbon fiber has excellent properties such as high strength, high modulus, low density, and heat-resistant. It is widely used in aerospace, defense, and all fields of national economy. At present, the main problem of our carbon fiber industry is the quality of PAN precursor is not good enough. The study on the rheological properties of PAN spinning solution will help to optimize the spinning process and improve the quality of PAN precursor. The rheological behaviors of poly (acrylonitrile-co-itaconic acid) solutions in dimethyl sulfonxide (DMSO) were investigated systematically in this paper. This paper tested the steady and dynamic rheological properties of polyacrylonitrile spinning solutions under different conditions by Anton Paar Physica MCR 501 rheometer, and this paper discussed the effects of temperature, concentration, molecular weight and shear rate on the apparent viscosity, the zero shear viscosity, non-Newtonian index and the structural viscosity index of PAN spinning solutions under steady rheological test. This paper also studied the dynamic viscoelastic properties of polyacrylonitrile solutions under dynamic rheological test and calculated activation energy of PAN solutions with different molecular weight by time-temperature equivalence principle. The results showed that the activation energy Ea of PAN solution increases with the decrease of molecular weight. In addition, this paper also focuses on the impact of several metal ions on the rheological properties of polyacrylonitrile spinning solutions. Three kinds of metal ion complexation were prepared by mixing Cu, Ni2+, Mg2+ /DMSO solutions with PAN/DMSO solution. The steady and dynamic rheological properties of the metal-PAN complexes system were studied, the results showed that the complexing abilities varies from different metal ions, the order is Cu2+> Ni2+> Mg+, while the viscosity and the modulus of the complex are proportional to their complexing ability. The results also showed that the existence of metal ions will reduce the activation energy Ea of PAN/DMSO solutions, and the activation energy Ea of PAN solution decreased with the increase of the complexing ability of ions, which contains Cu2+ ions has a largest decrease in the activation energy Ea of PAN solution.