Abstract: Effects of rosemary antioxidant (RAO) on the antioxidantive properties of PP were evaluated by comparing the rheological and mechanical properties before and after natural weathering. For neat PP, after 150d’s aging, the tensile strength decreased from 32 to 24Mpa, the melt flow rate increased from 2.7 to 18.8 g/min; after 30d’s aging, the impact strength decreased from 3 to 1 kJ/m². For RAO containing PP at the same conditions, the tensile strength from 34MPa to 29Mpa, the melt flow rate increased from 2.5g/min to 5.3g/min, the impact strength decreased from 4 to 3.2 kJ/m². In the melt torque determination, the torque of RAO containing system was obviously higher.

Key words: polypropylene, rosemary antioxidant, natural antioxidant, natural weathering test