Abstract: The sodium salt of long chain fatty acid and sodium of arylamide fatty acid were compounded to form a compounding nucleating agent （SCAB）， and its effect on the crystallization and mechanical properties of polypropylene （PP） was investigated. The results indicated that the molecular structure of SCAB was not changed during its compounding process or at the processing temperature of PP， and its intermolecular aggregation state was significantly improved by the compounding process. The nucleated PP showed a significant increase in the crystallization rate， notch impact strength， and tensile strength with the extension of the carbon chain length of sodium salt of long chain fatty acid. The compounding did not affect the crystal growth mode of PP. Owing to the excellent dispersibility of SCAB in the PP matrix， a combination of SCAB with sodium stearate could refine the PP spherulites effectively and improve its crystal structure. This resulted in an increase in the crystallization rate of PP by 6.3 times， in the notch impact strength by 27.3 %， and in the tensile strength by 8.2 MPa.

Key words: polypropylene, long chain fatty acid sodium salt, sodium arylamide fatty acid, compounding, crystallization property, mechanical property