Tertiary Recycling of Plastic Solid Waste for Additive Manufacturing

Abstract

Thermoplastics have a high utility in various engineering applications for a variety of consumer products. These products can be suitably prepared by additive manufacturing (AM)–based 3D printing processes for high-end customization. The plastic solid waste (PSW) generated around the globe from excessive use of thermoplastics has serious environmental issues. Recycling of PSW in terms of a material processing route may contribute significantly in the management of waste plastic and increase the functional application of the recycled material for advanced 3D/4D printing applications. The present study reports the tertiary (3°) recycling of PSW as a novel material processing method to reuse the waste thermoplastics for AM-based fused deposition modeling (FDM) process. Graphene nanoparticles (GNP) and Mn-doped ZnO powders were blended with recycled polyvinylidene fluoride (PVDF) pallets in the presence of di-methyl formamide (DMF) solvent for uniform blending. The composite was tested for rheological (melt flow index (MFI), viscosity), thermal (heat capacity, thermal stability), mechanical (peak and break strength), and morphological (shore-D hardness and porosity) properties for 3D printing applications. A further process capability analysis was performed to investigate the suitability of the proposed 3° recycling process for batch production. The results of the study outlined that 3° recycling resulted in preparation of a composite that possesses good flow ability, thermal stability, mechanical strength, and morphological properties for fabricating 3D-printed functional prototypes of recycled PVDF. Also, 3° recycling of PVDF to prepare the proposed composite may be considered a novel material processing route to manage the industrial waste of PVDF on a large scale to manufacture 4D-capable functional prototypes.