Abstract (EN):
Various food grade polymers(1) were tested to determine their tribological performance in dry sliding against AISI 316 stainless steel. Tests were made with a block on ring tribometer in order to measure the friction coefficient and the wear rate, under three different dry friction testing conditions. It was possible to conclude that, under the conditions used the polymer ultra high molecular weight polyethylene (UHMW-PE) green presents very low friction coefficient and wear rate values. The contact surface of the stainless steel rings and polymers was observed by optical microscopy and scanning electron microscopy to evaluate the involved wear mechanisms. Stainless steel and polymer wear debris were detected, which leads to the conclusion of the presence of wear mechanisms such as: adhesion, abrasion and thermo-oxidative wear. Another aim of this work was prompted by a real application in a sugar conveyor, in order to find which of the tested polymers would better resist to the wear caused by the insertion of sugar at the interface. Using the same block on ring tribometer, but modified to insert sugar at the contact zone, new tests have been performed under the same conditions. It was verified that the polytetrafluoroethylene (PTFE) wear debris form a barrier to the sugar inlet, while polyethylene terephthalate (PETP), although not preventing the sugar entrance into the interface, showed the lowest wear rate among all the polymers tested. The ideal polymer could be a composite of PETP and PTFE in such a percentage that the friction coefficient was reduced and it was able to form an efficient barrier to sugar entrance at the interface. (C) 2002 Elsevier Science B.V. All rights reserved.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
9