Characterization of polyetheretherketone particle suspensions for electrophoretic deposition

Abstract

Suspensions of polyetheretherketone (PEEK) using mixture of ethanol and isopropanol as solvent were prepared to carry out PEEK electrophoretic deposition (EPD). The rheological behavior and suspension structure of PEEK particles dispersed in co-solvents were investigated over a range of pH values (1-10) and shear rates (γ = 101-3 × 102 s -1). These PEEK suspensions generally exhibited a pseudoplastic flow behavior, indicating the occurrence of particle aggregation in the liquid medium. The maximum solids fraction (φm) showed an estimated value of φm = 2.9 wt %. Using a suspension with 3 wt % PEEK concentration, PEEK coatings on stainless steel substrates were obtained by EPD at constant voltage condition. The influence of the electrolyte conductivity on PEEK EPD from ethanol-isopropanol suspensions was studied. Experimental results showed that high-conductivity ethanol-based suspensions yield non-uniform deposits, while low-conductivity suspensions resulted in uniform coatings. The difference in the deposition behavior is due to the different pH of the suspensions and the relationship of pH with suspension conductivity. pH = 8 was the optimal value for this system in terms of deposition results. The surfaces of EPD PEEK coatings were homogenous and a qualitatively good adhesion between the PEEK deposits and the substrate was confirmed. © 2014 Wiley Periodicals, Inc.