2 Experimental2.1 Melt SpinningPET chips with inherent viscosity of 0.62 dl/g was used for the study. Molten polymer was extruded at 293°C through a single hole spinneret of 1 mm diameter at a mass flow rate of 5.4 g/min. The filament was wound with a high-speed take-up device kept at a distance of 330 cm below the spinneret. Take-up velocity was varied from 1 to 7 km/min.A LIB was placed in the spinline as shown in Fig. 1. Theliquid temperature in the bath was maintained at 155°C bypumping up the heated liquid from a reservoir to the bath.The depth of the liquid was 10 cm and the liquid mediumused was propylene glycol. The surface level of the liquid wasset at 150 cm (LIB 150) or 200 cm (LIB 200) below thespinneret. It is well recognized that the temperature profileof the spinline strongly depends on the spinning temperatureand the mass flow rate, whereas the velocity profile of thespinline does not have any significant influence on thetemperature profile. Under the spinning conditions stated