Influence of a novel drying technique on the mechanical per-formance of recycled and virgin PET

CAMPOS, GABRIELA C.; MORALES, FEDERICO; YAMILA ALONSO; PETTARIN, VALERIA; ALEJANDRA COSTANTINO

Guimaraes

Conferencia; International Conference on Polymer Process Innovation | PPI 2023; 2023

Plastic materials are essential in modern societies; they come mainly from fossil resources. That is why recycling is a very important step in the transition towards a circular economy, to avoid continuing to use fossil re-sources and thus close the cycle of production. PET is currently considered one of the plastics with the greatest po-tential for be recy-cled due to its good properties and ability to be processed by industrial processing. However, those processes may deteriorate its properties, such as tensile strength or thermal stability, since they involve high tem-peratures and shear stresses that together with the presence of moisture (due to the strong hydrophilic nature of PET) can accelerate the thermal oxidation of the polymer with a corresponding loss in molecular weight. When work-ing with recycled PET the excess moisture contained in the material may be higher. Despite the importance that rep-resents the drying stage for this resin, it has not yet been studied how different techniques of drying can influence the final mechanical properties of the processed parts and the cycle total (time/costs). In the present work, two dry-ing techniques were applied, one conventional through an oven widely used in the industry and another novel one through infrared rays (which involved the construction of an infrared oven) to study its influence on the cycle of re-cycled and mainly in the final mechanical properties of PET parts obtained from of waste soda bottles and virgin ma-terial used for comparison. It was found that drying by infrared technology reduces drying time by 80% which implies a Drastic reduction in total recycling time for all materials (recycled and virgin). In addition, no significant differences were found in the conventional and non-conventional mechanical properties, which indicates that drying by infrared technology does not degrade or affect negatively the performance of the materials used in the present work.