Optimization of PET bottle recycling for filament production: a comprehensive study on 3D printing parameters and material properties
The abstract describes the assembly process of a device for recycling PET bottles into filament, outlining the adhesion problems and 3D printer parameter settings that arose during the 3D printing of parts for the setup, along with proposed solutions to these issues. A prototype setup for producing filament from PET bottles has been developed and manufactured, which can also be used as an element of plastic waste recycling technology. During the 3D printing of setup parts from PLA plastic, 3D printing problems were identified and analyzed. Recommendations are provided for eliminating these shortcomings by optimizing printing speed, temperature, infill density, and layer thickness parameters. The structure of the experimental setup and methods for processing the obtained data for calorimetric, thermomechanical, and mechanical analysis are described. The results of measurements of PET characteristics before and after recycling into filament were studied. The temperatures of the main transitions of PET filament from glassy to highly elastic and viscous states were determined. From the mechanical analysis, the modulus of elasticity, yield strength, and fracture point were analyzed. A comparative analysis of PET before and after recycling into filament was conducted. Mechanical tests showed that the stress and strain yield of PET filament are lower than those of PET plastic before recycling. The Young’s modulus and tensile strength for PET filament are the same within the margin of error, but the elongation at break is almost half of PET plastic before recycling. Using DSC and TMA analysis methods, it was established that the glass transition, melting, and crystallization temperatures, the enthalpies of melting and crystallization, the coefficient of volumetric expansion, and the degree of crystallinity for PET plastic before recycling into filament and the filament itself do not differ within the margin of error.