Abstract:Polymorphism (α-, β-, andγ-crystals) is an important feature of isotactic polypropylene (iPP). Of these polymorphs, the formation laws and mechanisms of α- and β-crystals have been widely concerned at present. Although there are respectable studies on γ-crystals, inductive articles have not been reported. This paper summarized the research situation of γ-crystals, which contains information about an introduction of the structure and morphology of γ-crystal, the factors and mechanisms that affect formation of the γ-crystals, such as molecular chain structure, adding a second phase, molding conditions (temperature, pressure, flow). The relationship between the structure and properties of γ-crystals was also introduced.