The application note discusses the use of the PerkinElmer Pyris™ DSC 9 in analyzing recycled polyethylene. Differential scanning calorimetry (DSC) offers insights into thermal properties like glass transitions, melting points, and recrystallization, helping differentiate polymer grades. The study involved heating and cooling polyethylene samples to assess thermal behavior and history, aiming to standardize conditions for comparison. Results demonstrated the utility of DSC in identifying virgin low-density (LDPE) and high-density polyethylene (HDPE), setting reference points for unknown grades. The PerkinElmer Pyris DSC 9, coupled with Pyris software, offers a precise, automated approach to polymer characterization, essential for assessing recycled polyethylene's quality and composition.