We studied tensile properties and rheological properties of a recycled HDPE that was obtained from PET bottle caps and a virgin high density polyethylene (HDPE) which was the molding grade for PET bottle. In the previous study we concluded this recycled HDPE had the same dependency of the material properties on the averaged molecular weight as the virgin HDPE. However, a 1mm - thick sheet and 0.1 mm - thick film of the recycled HDPE was brittle compared to a sheet and a film from the virgin HDPE. We also found that the dependence of the tensile fracture energy on the duration of UV irradiation was essentially the same in these samples. In the case of the HDPE samples we could validate the theoretical equation that the authors proposed for the recycled polypropylene. Then we observed their morphology using TEM. Images were seen in Figures 5 and 6. At last we found the recycled HDPE melt had thermo-rheological complexity like LDPE. After UV irradiation the virgin HDPE had thermo-rheological complexity, too.