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To clarify the characteristic behavior of filament deformation in high-speed in-line drawing process of poly(ethylene terephthalate) (PET), on-line measurements of filament velocity and diameter were performed. In the process, velocity of the first godet roller was fixed at 2 km/min and the draw ratio was varied from 1.75 to 2.25 by changing the velocity of the second godet roller from 3.5 to 4.5 km/min. For comparison, on-line measurements were also performed for the high-speed melt spinning process at take-up velocities of 2 to 5 km/min. Diameter and velocity profiles of PET filament in the high-speed in-line drawing process indicated that the filament started to deform immediately after passing through the first godet roller (GR-1), and finished its deformation at 40 ~ 60 cm from the GR-1. The region of deformation became narrower and shifted toward the GR-1 with an increase in the draw ratio. Detailed analysis of necking deformation through simultaneous diameter measurements at two positions of close distance revealed that the position of necking deformation fluctuates along the drawing-line and its shape varies significantly depending on the direction of its movement. When the position of necking deformation was shifting toward the upstream, its shape was steeper than the one shifting toward the downstream. Results of the simultaneous on-line measurements of diameter and velocity supported this conclusion qualitatively. The analyzed maximum strain rate at the draw ratio of 2.0 reached a high value of 510 s– 1.

The experimental study of mixing polymer (polypropylene, PP) with mineral filler (Talc) by both simultaneous and separate feed system in a twin screw extruder was described. In this study, melt flow rate (MFR) of PP, talc particle size and talc mixing ratio to PP were selected as parameters of interest. It was found that these parameters had influences on the maximum throughput rate of mixture. In the cases of constant talc particle size and mixing ratio while MFR of PP was varied from 1.8 to 33, it was observed that throughput rates of all mixtures with different MFR values increased as a function of screw speeds. Throughput rates of the mixture of lower MFR PP (MFR = 1.8) were slightly lower than those of the higher MFR mixture (MFR = 10, 33) for both simultaneous and separate feed systems. With regard to effects of talc particle size, compounds having fixed talc mixing ratio showed lower throughput rates when talc particle size was smaller. In the case where talc mixing ratio was varied, compounds with fixed MFR of PP and talc particle size showed lower throughput rates when talc mixing ratio was larger. The mixing state in the mixing zone was also observed. Based on the overall findings, the mechanisms of filler mixing were clearly understood. The observed mixing patterns were similar for both simultaneous and separate feed systems. It was found that the elimination of the air accompanying the filler when the filled polymer mixture passed down the extruder is important for mixing. Through the experimental observations, the schematic diagram, the model and the flow chart of the proper filler mixing process were proposed.