Rheological modification of recycled poly(ethylene terephthalate): Blending and reactive extrusion

The use of recycled PET (rPET) in long-term applications, such as composites, may provide an environmentally friendly solution for PET wastes. Main problem to overcome to use rPET in composites is its high viscosity which compromises the impregnation with the fibers during the consolidation process. As it is well known, PET undergoes thermo-mechanical and hydrolytic degradation during its mechanical recycling decreasing its viscosity and causing a loss of mechanical properties. For this reason, this paper takes into consideration a rheological modification during mechanical recycling to achieve the necessary fluidity for composites while maintaining the mechanical properties. Rheological modification was carried out by physical and chemical methods. Physical method was realized through blending with virgin PET (vPET) of low melt viscosity. Chemical method was performed on rPET, vPET and its blends by reactive extrusion. The effect of rheological modifications on the final thermal and mechanical properties was studied. Main results showed that both methods are able to decrease the viscosity without compromising mechanical properties. In addition, the chemical method during the reactive extrusion provided higher Elastic Modulus values.