Rheological property of partially cyclized polyamide acid and electrospun fibers thereof

Partially cyclized polyamide acid(PAA) solution was electrospun into nanofibers.The rheological properties of different PAA solutions and the mechanical properties of the resulting nanofibers were discussed.IR spectrum and SEM were used to characterize the imidized extent and surface morphology of nanofibers.The results showed that increasing the amount of cyclizing agent increased the imidized extent of PAA,the viscosity decreased when the shear rate increased,and more rigid the molecular chains,more obvious the decreasing of viscosity.Increasing the viscosity of the solution,the nanofibers became straight and the fiber diameter increased.The PAA nanofiber sheet′s maximum tensile strength and elastic modulus were about 16.87、(254.77 MPa),respectively.