Evaluation of the mechanical and rheological properties of recycled high density polyethylene (HDPE), with the addition of crosslinking agent and gamma irradiation process

High density polyethylene (HDPE) is a thermoplastic material with good mechanical properties and general use in the industry, mainly processed and molded by blowing, extrusion and injection. Its low cost and easy processing make HDPE one of the most used materials in the manufacture of various products, such as bottles, drums, fuel tanks for automobiles, toys, household products and packaging. In Brazil, it is the second most used thermoplastic representing 13.5%. As a thermoplastic, its recycling occurs through the extrusion process however, with significant loss of mechanical properties. The objective of this work was to study an additive used as a crosslinking agent for granulated and ground materials, comparing the results obtained with irradiated samples. This additive is added to granulated and ground materials, without extrusion, being used by means of conventional injection. Seeking the same properties as a material reprocessed by extrusion, with the advantage of manually adding the additive to the ground material, in a practical and fast way. The material of the present study was the high density polyethylene (HDPE) reprocessed and grounded high density polyethylene (HDPE). It was divided into 3 additive applications (0.4%, 0.7% and 1%) and two irradiation doses (20 and 50 kGy). The additive is produced by means of low density polyethylene (LDPE) granules coated superficially with a small amount of organic peroxide Di- (2-tert-butyl peroxy-isopropyl) -benzene, with partial crosslinking. The tests carried out with the addition of the crosslinking agent showed improvement in its mechanical properties. This work can contribute by facilitating the use of recycled HDPE in a more practical and efficient way, taking into account industrial and environmental demands from the addition of additives. (author)