A STUDY OF THE FLOW PROPERTIES OF GLASS-FIBER-REINFORCED PBT IN EXTRUSION

The extrusion shaping process of polymer materials is a course of poly mer deformation, molten now and solidification shaping. The melt now c haracter is one of the important parameters of polymer process-ability ; it is usually expressed by a viscosity or flow curve. In the present study, the end effect and the now properties of glass fibre reinforce d PBT melt POCAN B4235 during extrusion have been investigated by usin g a Rheovis 2100 capillary rheometer. It has been found that the suita ble extrusion temperature range of the sample is 240 similar to 250 de grees C. Within the apparent shear rate ranged from 50 to 1000 s(-1), the now properties of the sample melt do not obey the power law. The r elationship between the shear stress at the wall and the apparent shea r rate is approximately linear. Under the lower extrusion temperature and apparent shear rate, the apparent shear viscosity of the sample me lt has been found to be sensitive to the apparent shear late. The depe ndence of the apparent shear viscosity on temperature does not agree w ith the Arrhenius equation The entry effect of the sample melt is sign ificant and the relationship between the entrance pressure drop and th e apparent shear rate basically obeys the power law under the experime ntal conditions.