Mechanical and Morphological Characterization of Recycled Low Density Polyethylene and Polystyrene Blends at Varying Compositions

Abstract

This study investigates the mechanical and morphological properties of recycled low-density polyethylene (RLDPE) and recycled polystyrene (RPS) blends at varying compositions. Waste LDPE and PS were collected, processed, and compounded at ratios of 90/10, 70/30, 50/50, 30/70, and 10/90 using a two-roll mill. Tensile strength, tensile modulus, and impact strength were evaluated for each blend. The results shows that tensile strength increased  from 8.5 Mpa for pure RLDPE  to 12.2 Mpa at 50/50 bend, but decreased to 10.5 Mpa at higher RPS content. The tensile modulus showed a significant improvement from 140 Mpa in RLDPE to 380 Mpa in the 90/10 blend, reaching a peak of 650 Mpa in the 10/90 blend due to the rigidity of RPS. However, impact strength declined from 48 J/mm² in the 10/90 blend, highlighting the brittleness introduced by higher RPS content. Scanning electron microscopy (SEM) revealed phase separation in all blends, with poor interfacial adhesion between RLDPE and RPS, Particularly at higher RPS compositions. This study underscores the potential for tailoring recycled polymer blends for specific applications, though further improvements are necessary to enhance interfacial compatibility and mechanical performance.