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Abstract Polyphenylene sulfide (PPS) is easily oxidized at high temperature, which greatly limits its applications. In this study, a nano-SiO2 compound antioxidant (SiO2-g-AO) was prepared and incorporated into PPS by melt compounding to obtain PPS/SiO2-g-AO composites. SiO2-g-AO was prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl) (antioxidant AO) with an aminosilane coupling agent (KH792). Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) confirmed that the antioxidant AO was successfully immobilized on the surface of SiO2 and the thermal stability was improved. Scanning electron microscopy (SEM) images showed that SiO2-g-AO was uniformly dispersed in PPS. It has been found that the crystallinity and mechanical properties of PPS composites improved, and the dynamic oxidation induction temperature (OIT) increased in the range of 16.7°C–21.1°C. A synergistic anti-oxidation model of nanoparticles and antioxidants, namely a multi-stage antioxidant system, was established by comprehensive analysis of experimental results. The synergistic anti-oxidation model provides a new idea for the antioxidant modification of polymer composites.

In order to explore the catalytic effect of alcohols on the 1,3-proton transfer of 1,1-diphenyl-N-(1-phenylethylidene) methylamine, the reaction potential energy surface was systematically studied at the theoretical level of ωB97-MV / def2-QZVPP // PBE0(D3BJ) / 6-31G**. The results show that the catalytic mechanism of benzyl alcohol can be divided into the acid channel and basic channel, in which the acid channel is the dominant one. In the first step, benzyl alcohol protonated the nitrogen atom of imine to form imine cation and benzyl alcohol anion, and the newly formed benzyl alcohol anion preferentially combined with the proton on C1; in the second step, benzyl alcohol continued to protonize the C3 atom, and the newly formed benzyl alcohol anion combined with the hydrogen on nitrogen, thus completing the whole proton migration process. By means of wave function analysis, it is proved that the stronger the hydrogen bond (O–H···N) is, the lower the free energy barrier is. When alcohols with lower pKa values are used as catalysts, the reaction barrier will be lower.