Study on the solid-state shear pulverization process in single screw extruder illustrated
by polyethylene as an example
Polimery 2004, No 3, 202
Investigations were carried out in a conventional single-screw extruder equipped with modified heating system of a cylinder, which of the first zone was heated and the other one cooled. Four thermoplastic polymers were the subjects of investigations: PE-HD, PE-LD, PS and PP. >From among them only PE-LD undergoes the effective pulverization in the extruder used. The effects of speed of screw rotation as well as temperature of heating of a cylinder conversion zone on size reduction degree of PE-LD pulverized were determined. It has been stated the fine PE-LD powder formed in the wide ranges of these parameters and energy demand appeared to be relatively small. Second zone of a cylinder (feeding zone) should be intensively cooled because only in such case the polymeric powder was most fine. The use of a special screw tip let take it off quickly from the cylinder immediately after the process interruption and, as a consequence, let characterize the solid bed. PE-LD pulverization goes rapidly at narrow temperature range below the temperature of polymer melting.
Keywords: pulverization, solid state shear extrusion, single-screw extruder, low density polyethylene, temperature of a cylinder, size reduction degree
Study on the solid-state shear pulverization process in single screw extruder illustrated by polyethylene as an example