Polyaceticzirconium for zirconia continuous fibers: Polymeric evolution process and the relationship between polymeric structure and rheological behavior

Polyaceticzirconium (PEZ) sol, which is the precursor of zirconia (ZrO 2 ) continuous fibers, has been synthesized by means of the reaction between zirconium oxychloride octahydrate (ZrOCl 2 ·8H 2 O) and potassium acetate (CH 3 COOK) in methanol. The polymeric structures and the rheological behaviors of the sols with different molar ratios of ZrOCl 2 ·8H 2 O/CH 3 COOK are different and would affect the spinnability and stability significantly. Herein, the polymeric structures and rheological behaviors of the PEZ sols with the molar ratios of 1:1, 1:1.5, 1:1.8 and 1:2 were investigated by Fourier transform infrared (FT-IR), 1 H nuclear magnetic resonance spectrum ( 1 H-NMR), thermogravimetry and differential thermal analysis (TG/DTA) and rheological measurements. The results showed the carboxyl group acted as a chelating ligand instead of bidentate ligand, and the water molecule coordinated to Zr 4+ was deprotoned gradually with the decrease of the molecular ratios. The different polymeric structures lead to a different rheological behaviors of the sols. It is divided into three types, the Newton fluid with a low viscosity produced by the charged linear polymeric structures, the shear thinning fluid with a high viscosity produced by the three-dimensional polymeric structures and the shear thinning fluids with a proper viscosity produced by the linear twining polymeric structures. Through the experimental guidance, we successfully synthesized a sol with suitable viscosity and stability, and used it to fabricate high quality ZrO 2 fibers.