In semi_crystalline polymer composites

when heterogeneous nucleation occurs with sufficiently high density along the interphase region

the resulting crystal growth is restricted to the lateral direction

so that a columnar layer develops around the fiber

known as transcrystallinity ( TC) or transcrystalline layers ( TCL) .The advance in the study of TCL in some fiber reinforced semi_crystalline polymer composites is reviewed in the present paper .It includes the formation and growth mechanisms of TCL

and the influences of TCL on the interfaces of fiber polymer and properties of composites .