Abstract: By shearing-drawing two-dimensional compound stress field pipe-extrusion die developed by the authors, two-dimensional reinforcement short glass fiber/high density polyethylene/polypropylene (PE-HD/PP/SGF) pipes were extruded. The molecule orientation of the pipes affected by the rotate speed of shearing sleeve and temperature of shearing stress field were studied in this paper. The results indicate that the molecular orientation of PE-HD/PP/SGF pipes was improved by the circumrotation of shearing sleeve. But the improvement dies down gradually along with the rise of the rotate speed and the temperature. The molecular disorientation of the PE-HD/PP/SGF pipes becomes more serious simultaneously.

Key words: short glass fiber, molecular orientation, high density polyethylene, polypropylene, pipe