Double-hindered phenolic SiO2 composites with excellent oxidation resistance and thermal stability for enhanced thermal oxidation stability of PPS

In recent years, loading antioxidants onto inorganic nanoparticles has attracted increasing interest. However, the existing studies not only have low antioxidant loading efficiency, but also ignore the relationship between structural changes and antioxidant properties before and after antioxidant modification, greatly limiting the improvement of the antioxidant properties of composites and their application scope. In this work, we successfully prepared bis-hindered phenolic antioxidants containing silica hydroxyl groups (Bis-mAO) and loaded them onto silicon dioxide (SiO2) to get the nanocomposites (Bis-mAO-SiO2). The melt blending method further prepared the corresponding polyphenylene sulfide (PPS)/Bis-mAO-SiO2 composites. The results showed that the higher antioxidant loading and more suitable antioxidant structure made Bis-mAO-SiO2 possess excellent antioxidant properties. The prepared PPS/Bis-mAO-SiO2 composites remained stable under high temperatures and oxygen environments. Impressively, the maximum weight loss rate temperature of PPS/Bis-mAO-SiO2 was increased by 11.60 °C compared to that of PPS, and after accelerated thermal oxidation at 220 °C for 24 h, the relative intensity ratio between O and C of PPS/Bis-mAO-SiO2 only increased to 0.086, much lower than 0.132 for PPS. Moreover, the viscosity of PPS/Bis-mAO-SiO2 only increased by 29.05 % and 88.75 % after accelerated thermal oxidation at 220 °C for 12, 24 h. Compared, PPS's viscosity increased substantially by 79.22 % and 250.3 %, respectively. This meant that the Bis-mAO-SiO2 successfully achieved a synergistic integration of high antioxidant properties and thermal stability, implying that the work offered a strategy for fabricating high-temperature resistant antioxidant composites.