Poly( ethylene terephthalate) ( PET)/carbon black (CB)masterbatch was prepared by melt blending using a separate feeding technique and its homogeneous dispersion morphology was confirmed by transmission electron microscope (TEM).The Avrami and Hoffman-Lauritzen secondary nucleation theories were employed to analyze the effect of high CB content on crystallization kinetics of PET,providing theoretical support for the development of masterbatch with high content of functional components.The Avrami exponents,average values of n,for PET and PET/CBmasterbatch are both greater than 3,which indicates threedimensional growth of crystals.In addition,no significant evidence for regime transition of PET is found applying Hoffmn-Lauritzen secondary nucleation theory,though such observations have been reported previously in the literature.Furthermore,appropriate U*value for PET is determined to be 12 800 J/mol.For PET/CB masterbatcb,a transition from regime Ⅰ to regime Ⅱ around 225 ℃ is observed with appropriate U* value (12 800 J/mol ).This phenomenon is consistent with a transition point in plot of G versus Tc.The fold surface free energy σe ( 100.3 mJ/m2 ) of PET is much greater than that of PET/CB masterbatch ( 48.3 mJ/m2 ),which indicates heterogeneous nucleation effect of CB particles.