Fused Deposition Modeling with Post-Consumer PP Recyclates: Processability and Mechanical Properties
Sprache des Vortragstitels:
Sprache des Tagungstitel:
In areas where material and product supply are limited, mechanical plastics recycling offers the chance to locally generate a feedstock for future applications. This is why versatile additive manufacturing is considered to play a key role in the development of the manufacturing sector in low-income countries, as no additional tools are required.
The aim of this work was to evaluate the suitability of post-consumer polyolefin recyclates for fused deposition modeling (FDM), as polyolefins are conventionally not used for FDM. Hereby, two PP recyclates sourced by informal waste pickers for Mr. Green Africa (Kenya) were compared to two commercial recyclates (PP & PE/PP blend) from Europe. After filament production, multipurpose specimens were produced by FDM with infill angles of 0° and 90°, respectively. Compositions were analyzed by DSC measurements, printability was evaluated, and mechanical properties were determined by means of tensile testing.
DSC results have shown that all recyclates consists partly of PE, which leads to the conclusion, that industrial and manual sorting are both limited to a certain degree of purity. Printing was influenced by warpage, which resulted in occasional detachment of the specimen from the printing bed. Therefore, the surface quality was reduced due to displacement of the molten filament. Furthermore, impurities that have been identified as PET in the Kenyan materials led to blockage of the die. The mechanical properties of the specimens printed with an infill angle of 0° were 10 ? 20 % lower compared to injection molded specimens. As expected, specimens printed at 90° infill angle represented the weakest material properties. While Young?s modulus and tensile strength were similar in both material sources, strain at break of the Kenyan recyclates was significantly lower due to present impurities. It can be concluded, that printability and mechanical properties are directly correlated with the purity of the recyclates.