Investigation Into the Fabrication and Weathering Resistance of Glycidyl Methacrylate Copolymer Modified Epoxy Prepregs and Transparent Composites

ABSTRACT In this study, transparent composites for lightweight photovoltaic (PV) module encapsulation were prepared using epoxy resin modified by glycidyl methacrylate copolymer (PGMA). The optical properties, thermodynamic properties, and weathering resistance of the transparent composites with different PGMA contents were investigated via rotational rheometry, differential scanning calorimeter, fourier transform infrared spectrometer, and dynamic mechanical analyzer. Additionally, the curing behavior and kinetic equation of the prepreg resin were elucidated. The results indicated that the enhancement effects of PGMA on the optical properties, weathering resistance, and thermodynamic properties of the composites initially increased and then decreased with increasing PGMA content. The optimal PGMA content was 10 wt%, yielding an initial light transmittance of 88.64%. After pressure cooker test and ultraviolet aging tests, the transmittance values remained at 84.82% and 82.64%, with retention rates of 95.7% and 93.2%, respectively. Compared with transparent composites without PGMA, retention rates increased by 4.8% and 4.5%, while the yellowing index (ΔYI) decreased by 24.7% and 33.7%, respectively. The curing reaction of the prepreg resin system exhibited an autocatalytic effect, described by the kinetic equation , with the maximum reaction rate occurring at a conversion of 0.3. Using this transparent composite to replace glass as the front‐sheet encapsulation material reduced the weight of the PV modules by 70%, thereby meeting the demand for distributed PV generation on urban buildings with low‐load‐bearing or curved roofs.