Structural and Thermal Assessment of POE Encapsulant Residues from Laser-Treated Photovoltaic Laminate Fragments

End-of-life photovoltaic modules represent a complex waste stream in which polyolefin elastomer (POE) encapsulants are increasingly important but insufficiently characterized after recovery. This study evaluates the structural, morphological and thermal state of POE-rich encapsulant residues obtained from laser-treated fragments of a crystalline-silicon photovoltaic module after approximately five years of field operation, focusing on material quality rather than process optimization. Reference POE and representative polymer-rich residues were examined by FTIR-ATR, TGA/DTG under nitrogen and SEM/EDS. FTIR-ATR showed characteristic polyolefin bands at approximately 2915–2847, 1463 and 718–719 cm−1 in both reference POE and treated residues, indicating retention of the hydrocarbon backbone. Treated residues exhibited additional features in the 1800–1500 and 1100–1000 cm−1 regions, attributed to oxygen-containing surface species and interfacial glass/silicon contributions. TGA/DTG revealed a similar main decomposition range for the POE-rich residues, with DTG peaks mainly between 471.5 and 474.3 °C, while residual mass varied from 1.94 to 23.03%, compared with 0.04% for reference POE. SEM/EDS confirmed heterogeneous surfaces and local silicon/oxygen-rich particles attached to or embedded in the polymer-rich residues. The results show that POE-rich waste fractions can preserve the main polyolefin structure, but their valorization requires control of inorganic contamination, especially for cut, cracked or mechanically damaged modules.