Characterization of Molar Mass Changes in PET Backsheet Films

This application note presents the use of Differential Scanning Calorimetry (DSC) to characterize molar mass changes in degraded Polyethylene Terephthalate (PET) photovoltaic module backsheet films. The study outlines the degradation process of PET when exposed to elevated temperatures and humidity, leading to hydrolysis and a reduction in molar mass due to polymer chain scission. The document details the experimental setup, including aging conditions and the use of Gel Permeation Chromatography (GPC) for quantifying molar mass changes. Results indicate a linear correlation between crystallization temperature and molar mass, demonstrating that DSC can serve as a rapid method for assessing polymer degradation. The findings emphasize the importance of understanding the stability of PET materials in photovoltaic applications, as degradation can lead to module failure and environmental concerns related to microplastic waste. The application note concludes with a discussion on the implications of these results for the PV industry.