The investigations on the structure and relaxation behavior of the amorphous phase are crucial for understanding the structure and property of crystalline polymers.In this review

we introduce the structures of the amorphous phase in crystalline polymers at first.Then

the effect of the morphology

molecular weight and crystallinity of the crystalline polymers on the relaxation behaviors of the amorphous phase in the crystalline polymers is described.The relaxation behaviors of the amorphous phase in crystalline polymers under confinement and in ultra-thin films are reviewed.The influence of extra force such as drawing

on the relaxation behaviors of the amorphous phase in the crystalline polymers is also discussed.As the amorphous phase plays an important role in the crystalline polymers

the effect of the amorphous phase on the mechanical properties and melting process of the crystalline polymers is discussed in detail in this review.At last

the structure evolution of the amorphous phase during the isothermal crystallization process of crystalline polymers is summarized.