Abstract:

Polypropene pipe (F401) was extruded using a home-made shearing/draw biaxial complex stress field die. Compared to regularly extruded pipes, the circumferential and axial tensile strengths of F401 were 21.4 % and 21.1 % higher, respectively, when the shear casing rotational speed was 10 r/min and the shear casing temperature was 190 ℃. F401 samples were characterized by SEM, WAXD, and DSC. It was found that the spherulites of F401 pipe was not obvious and arranged more regularly. The melting points drift to higher temperature and the degree of crystallinity increased. XRD showed the orientation in both directions of F401 was higher than regular ones.

Key words: complex stress field, biaxial self-reinforcement, polypropene, microstructure