For the fiber produced by a continuous multi-stage zone-drawing equipment by using four different polyethylene (hereafter"PE") samples in a range of medium high molecular weights, the relationship between fiber structure and mechanical properties was examined. The relationship between the stress of necking drawing in the first stage of continuous zone-drawing and birefringence of amorphous phase or young's modulus of the fiber obtained was linear, independent of the molecular weight. The relationship between young's modulus and the crystallinity showed a large variable dependence with a sharp rising point of the young's modulus. The crystallinity at the critical point is shifted to a higher value on increasing the drawing temperature or on decreasing the molecular weight.
These relations suggest that young's modulus influences greatly the construction of crystallite block structure and is increased by connection of crystallite blocks, which is also suggested to be related to the mobility of the molecular chain. On the other hand, the tensile strength depends mostly on the crystallinity and the molecular weight.