UV-Shielding and enhanced thermal stability of poly(vinyl alcohol)/graphene composites

UV radiation has short wavelength and high energy. Even though UV radiation is widely used in industrial processes and applications such as in detectors and medical diagnosis, prolonged exposure to it may result in harmful health effects and degradation on skin, eyes, and immune system of humans. Protection is therefore needed, and alternative UV shielding materials with enhanced performance and versatility are still required [1]. Alternatively, polymer-based shield material are being produced, because they are lightweight, conformable, and may be designed to include non-toxic materials. Attenuation is obtained by combining the load and structural material [2]. Graphene is a two-dimensional (2D) material with monatomic thickness with excellent properties, such as high electron mobility, high thermal conductivity, high mechanical strength, in addition to high transparency and surface area, making it a promising material for use in nanocomposites [3]. In this paper, few-layer graphene based nanocomposites of poly (vinyl alcohol) were tested for shielding of UVC (100−280 nm), UVB (280−315 nm) and UVA (315−400 nm) radiation. The nanocomposites were characterized by TGA, Raman and IR spectroscopy. Kinetic studies showed an increase of the activation energy of decomposition with the addition of graphene to the polymer matrix. The incorporation of graphenic nanostructures resulted in flexible films with also enhanced UV shielding properties. The results are promising and the absorbance of UV at 300 nm can be up to 80% for the nanocomposites with around 70% of transparency in visible spectral range and concentration as low as 0.5 wt% of nanocarbon.