Thermal Determination of the Ethylene-Vinyl Acetate Copolymer (EVA) and Polyethylene Terephthalate (PET) Ratio in Photovoltaic Module Waste

The rapid growth of photovoltaics (PV) contributes significantly to electronic waste, with projections estimating around 8 million tons of PV waste by 2050. A significant proportion of these are polymer materials like ethylene-vinyl acetate copolymer (EVA) and polyethylene terephthalate (PET), which may be recycled by means of pyrolysis. This study introduces a novel method based on thermogravimetric analysis (TGA) to determine the EVA/PET ratio in the polymer fraction of shredded PV module waste for pyrolysis optimization. Analysis of various artificially created EVA/PET ratios demonstrates that the first decomposition stage during EVA deacetylation is particularly effective for quantification, unaffected by inorganic materials. A cubic fit analysis of the first derivative of the TGA curves yields a high correlation (r<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.99). For the analyzed PV polymer waste mix, the method calculates an EVA/PET ratio of 2.52 ± 0.11, highlighting its potential for optimizing recycling processes in PV waste management.