Aya Tominaga

Thermal process-dependence of the mechanical properties and inner structures of pre-consumer recycled polypropylene

Recycled plastics are considered to have less-desirable mechanical properties and durability than virgin materials, and this is usually thought to be due to chemical degradation. However, we recently found that pre-consumer polypropylene (Pre-RPP) was not chemically degraded and had almost the same molecular properties as virgin polypropylene (VPP). In this study, we subjected recycled pre-consumer polypropylene to various thermal treatments and found that we could obtain properties similar to those of virgin polypropylene. We also investigated the fracture surfaces by SEM. The results showed that the mechanical properties were closely related to the inner structure, and if we can control the inner structure of Pre-RPP we may be able to improve its mechanical properties and durability so that they are almost the same as those of VPP.