Quartzo como estabilizante contra a fotodegradação de polímeros transparentes de painéis solares fotovoltáicos

Abstract

Plastic transparent materials exposed to solar light suffer photodegradation due to ultraviolet (UV) radiation. One particular case is the yellowing of the encapsulating polymeric material of solar panels with correspondent reduction in light transmittance to the silicon layer and loss in efficiency of the panel. In a recent work, Carvalho (2011), quartz particles were produced and submitted to gamma rays irradiation and they worked as stabilizer against photodegradation of a quartz + EVA compound. In the present research we tested other, lower cost, paths using quartz but without gamma rays irradiation. Only heat treatments and mowing were used. A new methodology was developed, including a quality factor to evaluate the adequacy of the samples to the protection of plastics against photodegradation. After heat treatments at temperatures ranging from ambient to 1100°C for 3 or 6 hours, the quartz samples were macerated in agate mortar or mowed in a spheres mill. The two kind of mowing reduced the average particle size. Mowing in a spheres mill also reduced crystalline grain size. Both effects, that is, reduction in grain and particle size, as well as the increase in quality factor, happen in the first minutes of mowing (15 min in the spheres mill) or maceration. Mowing for longer times do not change appreciatively the quality factor. The quality factors of our samples are similar or better than those from samples produced by Carvalho (2011) and that protected successfully polymeric films against photodegradation.