An exploratory model for predicting post-consumer recycled PET content in PET sheets

An exploratory model for determining post-consumer recycled polyethylene terephthalate (PET) content in PET sheets for one specific stream of mechanically recycled PET (RPET) was developed. Six kinds of PET sheets with varying percent of virgin (V) and recycled (R) PET contents (i.e., 100V, 80V20R, 60V40R, 40V60R, 20V80R, and 100R PET) were commercially extruded. The optical, thermal, physicomechanical and barrier properties of the PET sheets were evaluated as function of RPET content. Differences were found between the sheets for UV and visible light absorption in the regions 200-350 nm and 670-700 nm, respectively. Intrinsic viscosities of 100V and 100R PET sheets were different. A censored normal multiple linear regression model including thermal, physical, optical and barrier properties was the best-fit model to predict VPET and RPET content in PET sheets.