▎ 摘　　要

This article reports the experimental investigations of polyvinylidene fluoride (PVDF) matrix-based composite feedstock filament (reinforced with barium titanate (BTO) and graphene (Gr) for possible 4-D printing applications) using fused deposition modeling (FDM). The mechanical, rheological, thermal, and morphological properties of in-house prepared FDM filament are also reported. The FDM feedstock filament was prepared with a twin-screw extruder (TSE). The process parameters of TSE for preparation of smart material-based filament with uniform dispersion of reinforcement (BTO and Gr) in the PVDF matrix have also been explored. Finally, the prepared filament has been used on FDM setup (without any change in hardware/software) for printing piezoelectric sensor with 4-D capabilities. The results of the study suggest that BTO and Gr have significant effect on the melt flow index of PVDF. The composite prepared with reinforcement of BTO and Gr shows a continuous flow, along with better thermal stability (based upon differential scanning calorimetry analysis), when 10-20 wt% BTO was added to the PVDF matrix. The observed maximum peak and break strength of the PVDF composite was 29.57 MPa and 26.50 MPa, respectively. The scanning electron microscopy and energy-dispersive X-ray analysis results reveal that the filament prepared with 20% BTO and extruded at 200 degrees C with a screw speed of 40 r/min has better dispersion of reinforcement among the selected parametric settings. Finally, a piezoelectric response of 20 pC/N has been measured on the FDM-printed thermally stable sample suitable for 4-D applications.