POLYETHYLENE PRODUCTS MANUFACTURED WITH WELL-CHARACTERIZED RECYCLED RESINS

Recycling of thermoplastics recovered from waste products is an interesting issue for the great variety of convergent aspects involved in its consideration (i.e., ecologic, technologic, economic, etc.). In the case of specific applications of an already used resin (packaging materials, films, consumer goods. etc.), it is necessary to find the new set of processing conditions, the most adequate proportions of virgin and recycled material (if any) and the nature and the concentrations of contaminants. The materials tested in this work were blends of recycled and virgin resins and also included small amounts of contaminants. The blends containing different percentages of recycled resin were extruded under different sets of processing conditions. The results show important changes in these processing parameters as a function of percentage of recycled material. The extruded sheets were further characterized in order to establish the dependence of their mechanical properties on the above mentioned parameters. The final results of this study give an indication of the tolerances of each one of the studied factors for the case of polyethylene sheets which meet the specifications for a particular application.