Experimental Test
Figure 4 shows the relationship of the flow with respect to the pressure applied to the extruder for different temperatures of the extrusion process using pharma grade recycled PET. At 290oC, the mass flow variation is not so sensitive to pressure changes in the extruder. For the case of bottle grade recycled PET, the mass flow showed a minimum variation at 280 oC regarding the analyzed operating pressures. Finally, the experimental data were used for validating the mathe- matical model and Figure 5 shows the experimental mass flow of the pharma grade recycled PET and the respective calculated mass flows. The predicted results are very close to experimental data with a maximum error of 3 %. This result indicated that the model used to describe the performance of experimental set up is adequate.