Influence of pressure and temperature on the friction granular polymeric materials to the metal surfaces

Abstract

Field of production of plastic products is one of the most important fields of the world economy, problems of polymers have been investigating and disclosing in scientific and technical articles of various periodical publications around the world. The most efficient for processing of polymeric raw materials is extrusion equipment, including screw extruders. The successful establishment of the new equipment and managing the process of recycling depends on the accuracy of account of friction on the surfaces of working machines. The purpose of the research are analysis of movement of polymer granules in a feeding zone in screw extruder, experimental determination of friction coefficient of granulated polymeric material on a metal surface, determination of friction coefficient depends on the load and temperature, and changes defined dependencies on changes geometrical dimensions of the working bodies in the extruder. Research of the material movement in a feeding zone is important and actual task, because the performance of the aforementioned zone determines the productivity of the whole process. The research conducted for the two types of polymer granules – copolymer of ethylene with vinyl acetate (sevilene) and polystyrene. Analysis of the results showed a general decrease of friction coefficient with increasing pressure, but upon reaching the maximum values at almost all curves is a transition through a minimum, after which values is begin to rise. For the sevilene the average friction coefficient is increases with increasing a depth of a channel and for polystyrene – is almost independent of changes a depth of a channel. With increasing a temperature of a working surface value of friction coefficient for sevilene is increases but for polystyrene is decreases. The difference between the described dependencies for two researched types of polymer is explains the different form of granules and their mechanical properties, including the values of strength, friction coefficient, deformation at different temperatures