MELT SPINNING AND PROPERTIES OF POLYETHYLENE OXIDE FIBER

Abstract

Several grades of polyethylene oxide (PEO), ranging in the molecular weight from 1.8×105 to 1.56×106, were subjected to melt spinning by using a single screw extruder. The optimum spinning temperatures are summerized in Table 1, and the degradation of polymer molecules by melt spinning is also listed in Table 2.PEO, having the molecular weight of 5.4×105 ([η]=3.2) has the highest spinnabillity and it gave the thin fiber of 20 deniers.The degree of orientation of the as-spum fibers was estimated by three different methods, i.e., birefringence, thermal retraction, and X-ray diffraction. Birefringence was measured by using a polarizing microscope equipped with a Berek compensator. The elastic deformation of the as-spun fibers was evaluated from the specimen lengths before and after the equilibrium retraction; fibers were allowed to retract in silicone oil bath at 80°C for 15 min. The crystalline orientation function was determined for the as-spun fibers as the function of draft ratio (melt-stretching ratio in the course of spinning). Both the relations of the crystalline orientation function and the elastic deformation ratio to the draft ratio indicate that the drafting up to 100 times is effective to improve the orientation, while the birefringence increases significantly in the region of draft ratio from 6 to 20 and then levels off. The difference in these orientation behaviors may be caused by the amorphous orientation.The maximum values of birefringence, crystalline orientation function, and elastic deformation ratio are 0.026, 0.9 and 9.0, respectivity. (cf. Figs. 4, 5 and 10) Despite of the highly oriented structure, the tensile strength of the as-spun fibers is less than 1g/d, as shown in Table 3.