Influence of Modified sio2 Nanoparticles on the Photostability of Recycled Hdpe

Silica nanoparticles (SiO<inf>2</inf>) were synthesized and organically modified with hexadecyltrimethoxysilane (Mod-SiO<inf>2</inf>) to enhance their interaction with polymer. Composites from recycled high-density polyethylene (HDPE) were obtained by a melt blending method in the presence of SiO<inf>2</inf>. The properties and photostability of the new materials were studied, as well as evaluating the effect of the content and modification of nanoparticles. Before irradiation, the microhardness of HDPE/SiO<inf>2</inf> and HDPE/Mod-SiO<inf>2</inf> increased ca. 65% after incorporating 5 wt% of SiO<inf>2</inf> and Mod-SiO<inf>2</inf> into HDPE, independent of the nanoparticle modification. After irradiation, the microhardness increased for HDPE and HDPE/SiO<inf>2</inf>, which could be related to the increased degree of crystallinity of the polymers after photodegradation. In addition, nanocomposites with modified nanoparticles (HDPE/Mod-SiO<inf>2</inf>) presented higher storage modulus (E′) and loss modulus (E″) than neat HDPE and HDPE/SiO<inf>2</inf>. In general, the HDPE/SiO<inf>2</inf> and HDPE/Mod-SiO<inf>2</inf> nanocomposites showed lower degradation, evidenced by lower values of carbonyl index (CI) and chemiluminescence emission (CL), and higher M-<inf>v</inf> values when compared with the neat HDPE after irradiation, especially when 3 wt% of SiO<inf>2</inf> was incorporated into HDPE. Also, the good dispersion of modified SiO<inf>2</inf> within recycled HDPE could improve its mechanical properties and provide stability to photodegradation. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023.