Abstract: In this work, the interfacial tension between PA6/PP was studied by combining the breaking thread and the deformed drop retraction methods. The retraction behavior of polyamide 6(PA6) drops in polypropylene(PP) was on-line investigated，and the effect of compatibilizers on the interfacial tension between PP/PA6 was explored .It showed that the PA6 drops deformed under shear flow, and then retraded to spheroid under interfacial tension. The interfacial tension was 7.16 mN/m for PP/PA6 blends and decreased with introduction of the compatibilizer. The interfacial tension of different blends was in
the following order:γPP/PA6 > γPP/SEBS/PA6 > γPP/PP-g-AA/PA6 > γPP/PP-g-MAH/PA6

Key words: polypropylene, polvamidc 6;compatibilizer;breaking thread method;deformed drop retraction method