Abstract: Polypropylene is easy to aging under UV irradiation and thermal oxidation, which to some extent limits its application, especially in the field of civil engineering. In order to improve the ageing resistance of polypropylene, different proportions of reactive nano calcium carbonate（CaCO₃）were added into the polypropylene. Test results indicate that the anti-aging properties of polypropylene achieves the best level when adding 4% of active nano CaCO₃.

Key words: polypropylene; reactive nano CaCO₃; ageing resistance