Abstract: In this study， a core-shell structured ASA grafted copolymer latex with a core-shell ratio of 6/4 was prepared through two-stage emulsion polymerization， and the effects of the composition and content of aqueous antioxidants on the thermo-oxidative aging， mechanical， and apparent performance of the ASA grafted copolymers were systematically investigated. The results indicated that the ASA grafted copolymer exhibited the optimal thermo-oxidative aging performance at a waterborne antioxidant CPL/DLTP mass ratio of 2/3. The oxidation induction period of the ASA grafted copolymer increased significantly with an increase in the content of water-based antioxidants； however， the growth of the oxidation induction period seemed not to be significant with the addition of more than 1 wt% of water-based antioxidants. The oxidation induction period for the ASA grafted copolymer containing 1 wt% water-based antioxidant reached 73.1 min at 230 ℃ in air， and its resistance to thermo-oxidative aging was better than that without an antioxidant under the same condition. Its thermo-oxidative aging ability was more than 80 times that of the ASA grafted copolymer without any aqueous antioxidants under the same condition. There is no obvious effect of the composition and content of waterborne antioxidants on the mechanical properties of the ASA resin but an obvious effect on its apparent properties such as whiteness.

Key words: acrylonitrile-styrene-butyl acrylate, core-shell graft copolymer, water-based antioxidant, oxidation induction period, thermo-oxygen aging resistance