Study on the high efficiency antioxidant of polyoxymethylene

This article reports on the properties and uses of antioxidant F/B, a type of high efficiency antioxidant for polyoxymethylene (POM), consisting of the hindered phenolic main antioxidant, the secondary thermostabilizer phosphite ester, and lactone compound. Our experimental studies focused on the thermostabilization effect of antioxidant F/B on POM, which was measured by isothermal weight loss analysis at 220 degrees C, isothermal weight loss rate analysis at 222 degrees C, balance torque analysis, nonisothermal gravity analysis (TGA), oxidation induction time (OIT) analysis, and multiple processing and long-term aging analysis as compared to the commonly used antioxidant Irganox245 of POM. The results showed that the thermal stability of POM can be improved remarkably by using antioxidant F/B. The aging mechanism of POM under heat and oxygen was studied by the measurements of polarized light microscopy (PLM), differential scanning calorimetry (DSC), and X-ray photoelectron energy spectrum (XPS), which showed very slight changes of spherulites dimension, crystallinity, and the surface atom concentration after 15 days of aging at 140 degrees C. Furthermore, the small amount of degradation of POM only occurred in the amorphous region of POM. These experiments demonstrated that lower amounts of antioxidant F/B can reach the same level of thermal stabilization of POM as is achieved with higher amounts of Irganox245, and can replace Irganox245 for use in the production of POM, which can further improve the thermal stabilization and reduce the production cost of POM.