Effects of rheology on the interface of Pb(Zr, Ti)O3 monofilament composites obtained by co-extrusion

The production of lead zirconate titanate (PZT) fibres, 1-3, 3-1 and 2-2 composites for actuator and sensor applications through the thermoplastic co-extrusion process can be achieved by using a macro-scale preform shaped by two different extrudable mixtures. The main challenge of this method is the optimization of materials that can be co-extruded and at the same time maintain the preform geometry in the final product, without axial and cross-sectional deformation. In this work, rheological characterizations of PZT/polyethylene and carbon black/polyethylene feedstocks were carried out to produce monofilament composites by the co-extrusion process. To explore the interface instabilities resulting from the viscosity mismatch between the processed materials, the co-extrusion tests were performed varying the velocity of the piston during extrusion. Successful co-extrusion, with well preserved fibre morphologies and defined interface between the co-extruded materials, was achieved for viscosity ratios between the feedstocks ranging from 0.98 to 1.16. Outside of this range, interface distortions were observed.