Polypropylene material under simulated recycling: effect of degradation on mechanical, thermal and rheological properties

Thinking on the environmental industry, and to encourage the use of recycled polymer as raw material, a study of the properties of several extrusion-injection cycles was investigated. Mechanical, thermal and structural properties of the samples were carried out in this paper using tensile test, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and viscosity analysis. The collected mechanical results as tensile strength, Young's modulus and torsional modulus had shown that they were not significantly affected by recycling process. Thus, a slight decrease from 1034 MPa of neat PP to 978 MPa for the 6th recycled PP in the Young's modulus and 30 MPa for PP tensile strength to 24 MPa for the 6th recycled PP tensile strength. The viscoelastic behavior of the recycled polymer has been evaluated though dynamic mechanical thermal analysis and results have shown that the viscoelastic behavior is closely related to the polymer chain length.