ABSTRACT
Polyvinylidene fluoride - hydroxyapatite composite filaments were processed by twin-screw extrusion at different processing angular velocities and characterized by scanning electron and atomic force microscopies, differential scanning calorimetry and tensile tests. Polymer-ceramic composites with a 0-3 connectivity were successfully obtained. Regardless of the used processing parameters, all composite filaments present very similar melting (â¼152°C) and solidification (â¼139°C) points and elastic moduli (â¼1.0 GPa) for hydroxyapatite as dispersed phase in the composite with concentrations up to 25 wt%, indicating that they are adequate for twin-screw extrusion and 3D printing. However, the yield strength (â¼29 MPa), ultimate tensile strength (â¼36 MPa) and tensile point (â¼29 MPa) parameters are similar only for hydroxyapatite concentrations up to 15 wt%, once higher concentrations of hydroxyapatite as dispersed phase result in fragile samples (â¼50% lower for each studied property).