Structure Transformation of Polypropylene and the Change of Mechanical Properties of Polypropylene Induced by UV Light

The effects of UV irradiation on the morphologic,mechanical properties and surface structure of α-nucleated PP(α-PP),β-nucleated PP(β-PP)and neat PP were studied.The lower degradability was found in β-PP as compared to α-PP and neat PP.An increase in crystallinity on short-time exposure followed by crystallinity decreased with prolonged exposure was detected in all samples.The β-phase content in the crystallinity portion of β-PP increased on short-time exposure,followed by crystallinity decreased with prolonged exposure,α-phase content of β-PP increased after shot-time decreased,then remained constant after 312 h exposure.