Use of Recycled Poly(ethylene terephthalate)-Based (rPET) Blends in Additive Manufacturing Techniques to Prepare Sustainable, Tough, and Heat-Resistant Parts

The presented study was conducted in order to evaluate the correlation between the structural properties of recycled PET-based blends for materials using the three-dimensional (3D) printing technique. The recycled rPET resin was melt-blended with amorphous polyesters, poly(ethylene terephthalate) glycol (PETG), and poly(cyclohexylenedimethylene terephthalate) glycol (PCTG). The obtained blends were intended for the material extrusion printing method (MEX), while some of the samples were prepared by an injection molding technique. The study aimed to examine the impact of waste materials on the quality of products obtained in the MEX process. The tested materials were rPET/PETG and rPET/PCTG blends, and an elastomeric impact modifier was used to improve the toughness of the prepared composition. During the study, the reactive extrusion method was used for blend compatibilization. The samples were tested to determine their mechanical and thermal properties. A static tensile test, a Charpy impact test, and a hardness test were performed. Thermal analysis was performed by using HDT, DMTA, and DSC tests. The research showed that even a large share of the rPET material had a positive effect on the obtained mechanical and thermal performance of the tested samples. In addition, the annealed samples had higher values of HDT temperature as well as hardness and E modulus. The annealing procedure revealed that for heat-treated samples, the heat resistance was improved; however, in some cases, the warpage was present.