Application of Factorial Design to Study the Effect of Recycling of HDPE on Rheological and Mechanical Properties

In the plastic industry, scrap is common and can reach important amounts in some applications. For that reason, reprocessing in the format of mechanical recycling is pretty common among plastic industry for its simplicity and efficiency. However, the stated type of reprocessing causes the degradation of the proprieties of plastic. Hence, recycled plastic is mixed with virgin one. The objective of this work is the investigation of the effect of the variation of the fraction of the recycled plastic (X1) in virgin/recycled blends and number of recycled cycles (X2) using factorial design for HDPE. To attend this objective, two sets of specimens were injected according to 2² factorial design. Mechanical and rheological proprieties were characterized in terms of melt flow index, Vicat softening temperature, elastic tensile strength at 5% (\( \sigma_{\varvec{e}} \)) and tensile strength at yield (\( \sigma_{\varvec{m}} \)). Using nemrodw software, effects plots were plotted. It was depicted that X1 and X2 have no significant effect on \( \sigma_{\varvec{e}} \), \( \sigma_{\varvec{m}} \) and on Vicat softening temperature. Nevertheless, they have a significant effect on MFI.