MICROSTRUCTURAL EFFECTS OF DECONTAMINATION BY UV-C RADIATION OF MASKS AND FACE SHIELDS
UV-C radiation has been widely used for decontamination of environments and medical devices, especially during the Covid-19 pandemic. Although it is quite effective, little is known about the effects of multiple exposures on the microstructure of different materials, which can mainly interfere with their durability. Thus, this study aimed to evaluate the compositional, surface tension and morphological effects exerted by UV-C radiation on devices in routine use during the Covid-19 pandemic, such as masks and face shields, after different exposures to radiation. For this, samples of N95 masks, face shields and nebulization masks were prepared and subjected to decontamination by UV-C radiation using a commercial device, at different exposures: 0 exposure (control group), 1, 10, 30 and 90 exposures. Compositional changes were evaluated by Fourier transform infrared spectroscopy (FTIR); wettability was evaluated by surface tension and contact angle analysis, and morphological changes were analyzed by scanning electron microscopy. Statistical analysis was performed using the Kruskal-Wallis and Student-Newmann-Keuls tests, considering a statistical significance level of 5%. It was possible to evidence a positive relationship between the number of expositions and the compositional changes in the samples, mainly related to the plasticizer content of face shields and nebulization masks. The number of sterilizations caused changes in the wettability of N95 masks, probably as a result of the morphological changes observed. Thus, it can be concluded that UV-C radiation can change the microstructural characteristics of masks and face shields, in a positive relationship with increasing exposure time.