• Pinter, Gerald
• Frank, Andreas
• Koch, Thomas
• Hinczica, Jessica
• Messiha, Mario

Abstract

<p>In Europe, the amount of plastic waste which was recycled and further processed into new products was only about 13 % in 2020. One option to process higher volumes of post-consumer recyclates into new products is blending with virgin materials. In order to investigate the effect of recyclates on rheological and structural material properties, a post-consumer polypropylene recyclate (PPr) was added to a virgin polypropylene (PP-v) in different contents of 10 %, 25 % and 50 %, respectively. Mechanical and fracture mechanical properties were analysed and compared with initial conditions of the original virgin and recycled materials. In addition, the influence of two different recyclates (PP-r) was examined by using grades of a high (PP-r1) and low (PP-r2) melt flow rate (MRF). Results demonstrate that the blending of virgin material with recyclates had a clear influence on material properties. The MFR values increased with higher recyclate content. Tensile tests showed a reduction of the Young's modulus and the yield strength with increasing recycling content. While tensile test properties were significantly affected by a recycling content over 10 %, notched Charpy Impact strength started to change above 25 % and 50 % of PP-r1 and PP-r2, respectively. The resistance against slow crack growth (SCG) of the materials was analysed by the crack round bar (CRB) test. Results indicate that a small recyclate amount of 10 % does not significantly reduce the SCG resistance of the blend compared to the virgin material. However, the SCG resistance decreases dramatically with higher recyclate content.</p>

Topics

• impedance spectroscopy
• polymer
• melt
• crack
• strength
• yield strength