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

When PPS was invaded by free radicals, Bis-mAO-SiO 2 , which was uniformly dispersed in PPS with high thermal stability and antioxidant efficiency, quickly provided a lively hydrogen atom to combine with the free radicals generated at the early stage of oxidation, blocking the oxidation process of PPS free radicals and inhibiting the oxidative degradation of PPS to the maximum extent. [Display omitted] • Bis-mAO-SiO 2 containing bis-hindered phenolic antioxidant was innovatively prepared. • PPS/Bis-mAO-SiO 2 composite was manufactured via melt processing. • Bis-mAO-SiO 2 effectively retarded the oxidative degradation of PPS. • Provides a good insight for the antioxidant modification of PPS and other materials. 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 (SiO 2) to get the nanocomposites (Bis-mAO-SiO 2). The melt blending method further prepared the corresponding polyphenylene sulfide (PPS)/Bis-mAO-SiO 2 composites. The results showed that the higher antioxidant loading and more suitable antioxidant structure made Bis-mAO-SiO 2 possess excellent antioxidant properties. The prepared PPS/Bis-mAO-SiO 2 composites remained stable under high temperatures and oxygen environments. Impressively, the maximum weight loss rate temperature of PPS/Bis-mAO-SiO 2 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-SiO 2 only increased to 0.086, much lower than 0.132 for PPS. Moreover, the viscosity of PPS/Bis-mAO-SiO 2 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-SiO 2 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. [ABSTRACT FROM AUTHOR]