Polypropylene (PP) /ethylene-octene copolymer (POE) blends with different content of POE were prepared by mixing chamber of
a Haake torque rheometer. The crystallization behaviors and crystal structure of PP/POE blends were systematically investigated
by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarized optical microscopy (POM). The
results showed that PP spherulites became defective and the crystallization behavior was influenced intensely with the introduction
of POE. At the low content of POE, the addition of POE decreases the apparent incubation period (Δti) and the apparent total crystallization period (Δtc) of PP in blends due to the heterogeneous nucleation of POE, and small amount of β-form PP crystals form because of the existence
of POE. However, at high content of POE, the addition of POE decreases the mobility of PP segments due to their strong intermolecular
interaction and chain entanglements, resulting in retarding the crystallization of PP, decreasing in the amount of β-form
PP crystals, and increasing in Δti and Δtc of PP in blends.