ORALS

The purpose of our work was the application of instrumental and analytical methods for studying of changes that happen to plastic materials during the recycling process and the way they are affected by the additives. The research covered the studying of plastic materials microstructure, the specification of additives and the change of principal physical and mechanical properties during the recycling process. The plastic materials analyzed were polyethylene PE, polypropylene PP and polystyrene PS. As recycling process we used extrusion in industrial scale. For the studying of microstructure were used infrared FT-IR and Raman spectroscopy methods and scanning electronic microscopy SEM, equipped with energy distribution system EDS for the qualitative analysis of chemical elements. Moreover we used X-ray diffractometry method to study the crystalline structure and the ability to determine the additives when they contained more than 5% of the total mass. Among the physical properties determined were specific gravity, density, melt flow index MFI, viscosity and average molecular mass. Mechanical properties were determined on polymeric rods with different diameters using the tensile test in one direction. The results obtained show the structural changes and the physico-mechanical properties during the recycling process and the influence of additive on them.