The morphology and mechanical properties of poly(ethylene-octene) copolymers (POE) obtained by dynamic packing injection molding were investigated by mechanical tests

differential scanning calorimetry (DSC)

fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field. Further investigation has been done by DSC

FT-IR

and SEM in order to make clear the reason of that phenomenon. Finally

the hypothetical mechanism of POE microstructure formation under shear field has been proposed. For POE with low octene content and high molecular weight

orientation degree and mechanical properties both increase substantially under shear field. For POE with low octene content and low molecular weight

orientation degree and crystallinity increase under shear field

but it is not dramatically benefit for the mechanical properties. For POE with high octene content and high molecular weight

the shear field has little effect on the morphology and mechanical properties.