In this study, the graphite effect on the mechanical and fire‐retardant performance of low‐density polyethylene (LDPE) and ethylene‐vinyl‐acetate (EVA) foam composites was investigated. Polymer composites were prepared by melt mixing process and foamed by hot press molding at different graphite content (0, 3, 6, and 12 phr). Cone calorimetric tests through heat release rate (HRR) curves obtained, revealed a decreasing of 45% on peak heat release rate (pHRR) of foam composites LDPE‐EVA with 12 phr of untreated graphite content compared than those LDPE‐EVA foamed composites without graphite, which was attributed to the good distribution of graphite in the composite and more residual generates as thermogravimetric analysis suggested. Mechanical properties of polymer foamed composites with high graphite content do not show significant detrimental as a result to the formation of more uniform cells with smaller size incorporating a material with high modulus like graphite. The results suggest that polymer foam composites with graphite are suitable for the building and construction industry, in sealing and thermal insulation applications with good fire‐retardant performance.

The influence of residual wax content on the thermal, rheological, and mechanical behavior of two high‐density polyethylene (HDPE) samples from different lots of the same supplier was characterized. HDPE with a low wax content presented a higher melting temperature and a wider melting endotherm. A decrease in the degree of crystallinity and thermal stability of HDPE with a higher wax content was observed. Thermograms obtained by DSC indicated a small additional exothermic transition associated with the exclusion of residual wax. A higher wax content in HDPE produces a decrease in its viscosity due to a lubricating effect, which allows the sliding of HDPE chains of high molecular weight. In contrast, HDPE with lower wax content achieves greater elongational viscosity and melt strength. The mechanical testing results show that HDPE with higher wax content presented lower Young's modulus, tensile strength, elongation at break, and Izod impact strength than HDPE with lower wax content. The results obtained show that a relatively slight difference in wax content significantly affects HDPE properties.

This study aims to investigate the effect of ground tire rubber (GTR) treated by acetone on mechanical and morphological properties of ethylene-vinyl acetate (EVA) matrix. Polymeric EVA/GTR (0, 10, 20, 30, and 40 phr) compounds were achieved through extrusion and batch foaming process. TGA and NMR analysis revealed that oils and additives were removed from the GTR after the acetone treatment. Morphological characterization showed cell sizes below 100 μm in the compounds with treated GTR, which improved the mechanical performance of EVA/GTR compounds. The results indicated that the acetonetreated GTR are a suitable raw material to obtain foam compounds useful in vibrations absorber and isolation applications.