Avaliação do efeito do reprocessamento do polietileno de ultra alto peso molecular sobre suas propriedades mecânicas, térmicas e morfológicas

Abstract

The International Standard Organization (ISO) defines the UHMWPE as having a molar ratio of at least 1 million g / mol mass, which results in a minimum degree of polymerization of n ≈ 36,000 per chain. It is a polymer of the polyethylene family manufactured under elevated pressure at temperatures above the melting temperature of approximately 135° C, with percent crystallinity from 58% to 75% depending on the resin. The UHMWPE has very long and very tangled chains, distinctive property of other polymers. Among the advantages offered by this polymer, the most important are excellent sliding properties, impact resistance, fatigue resistance and abrasion resistance. When processed by machining, this polymer generates enough waste and leftovers that end up being discarded. Many industries end up not knowing what to do to this product. By having a high cost, it is interesting to know whether it is possible to reprocess and reuse this material. In this research we study the mechanical, thermal and morphological properties of UHMWPE before and after reprocessing, through the techniques of compression molding and RAM extrusion, in order to verify whether it is possible to reuse this material in the industry. The results showed that it is possible to reprocess the UHMWPE after the micronization process of sheets obtained from virgin product, without loss in relation to its mechanical and thermal properties. Comparing results of Charpy Notched Impact Strength, Slurry Abrasion and Static and Kinetic Coefficients of Friction, the reprocessed product achieved better results compared to the virgin product. Reprocessing also showed that the process of compression molding has better tensile properties in relation to the RAM extrusion process.