On Secondary Recycling of PVDF for 3D Printing of Functional Sensors: Mechanical, Flow, Thermal, and Dielectric Properties

Virgin polyvinylidene fluoride (PVDF) is widely used in numerous engineering and biomedical applications, hence requiring a scientific recycling solution to achieve the sustainable development goals of the United Nations. However, less has been stated on the effect of secondary (2°) recycling of PVDF to ensure the 3D printing of functional sensors. This study compares virgin and 2° recycled PVDF composite prepared by mechanical reinforcement (by wt.%) of 8% hydroxyapatite (HAp), and 2% chitosan (CS) with a single screw extruder (SSE) for the 3D printing of functional sensors. The 2° recycled PVDF composite was compared with virgin PVDF based on mechanical, flow, thermal, surface characteristics, and dielectric properties. The study outlines that 2° recycled PVDF composite may be used for the 3D printing of functional sensor prototypes with an improvement of Young’s modulus (E) (45%), viscosity (122.6%), and surface roughness (Ra) (6.79%) for the selected composition. However, the modulus of toughness (MOT) was significantly reduced (88.37%). Overall thermal and dielectric properties have shown little variation after 2° recycling.