抄録
The effects of molecular weight on melt spinning and drawing process of PEEK (Poly (oxy-1, 4 phenyleneoxy-1, 4 phenylene carbonyl-1, 4 phenylene) were investigated. Spinnability, drawability, crystallinity, orientation and mechanical properties were measured for fibers prepared from three different molecular weight PEEK. With increasing molecular weight, crystallization rate for unoriented fibers decreased, whereas that for oriented fibers with the draw ratio higher than 1.5 increased. This result relates to the occurrence of the strain-induced crystallization in the spinning of high molecular weight PEEK. The crystallization raised the spinline tension and caused cohesive fracture of the spinline at a high melt draw ratio. Thus, the maximum melt draw ratio for high molecular weight PEEK was lower than that for low molecular weight one. On the other hand, drawability in the drawing process was better for high molecular weight PEEK, since crystallization rate was low at the early stage of the drawing and the formation of spherulites and voids did not proceed to a great extent. Consequently, crystallinity, molecular orientation and mechanical properties for high molecular weight maximally drawn fibers were higher than those for lower molecular weight ones.
