From Disposal to Technological Potential: Reuse of Polypropylene Waste from Industrial Containers as a Polystyrene Impact Modifier

• Published in: Sustainability 2020-07, Vol.12 (13), p.5272
• Main Authors: Luna, Carlos Bruno Barreto, Siqueira, Danilo Diniz, Ferreira, Eduardo da Silva Barbosa, Silva, Wallisson Alves da, Nogueira, Jessika Andrade dos Santos, Araújo, Edcleide Maria
• Format: Article
• Language: English
• Subjects: Amorphous materials; Calorimetry; Consumption; Containers; Copolymers; Differential scanning calorimetry; Ductility; Elongation; Extrusion molding; Impact modifiers; Impact strength; Mechanical properties; Modulus of elasticity; Pollution control; Polystyrene resins; Recycled materials; Rheology; Rheometry; Scanning electron microscopy; Styrene; Styrenes; Sustainability; Sustainable development; Tensile properties; Tensile strength; Thermal stability; Twin screw extruders; Waste disposal
• ISSN: 2071-1050; 2071-1050
• DOI: 10.3390/su12135272

The practice of recycling over the years has been increasingly encouraged, with the aim being the manufacturing of materials that contribute to sustainable development. In light of this, the present work evaluated the potential of mixtures of polystyrene (PS)/recycled copolymer polypropylene (PPr), using styrene-(ethylene/butylene)-styrene (SEBS) as a compatibilizing agent. Initially, the mixtures were prepared in a co-rotational twin-screw extruder, and, afterwards, the extruded granules were molded by injection. The properties of torque rheometry, impact strength, tensile properties, differential scanning calorimetry (DSC), heat deflection temperature (HDT), and scanning electron microscopy (SEM) were evaluated. The formulation PS/PPr/SEBS (70/20/10 %wt.) demonstrated an increase in viscosity, corroborating with an increase of 123% and 227% in the elongation at break and impact strength, respectively, compared to neat PS. Though the elastic modulus and tensile strength suffered losses, the reduction was not drastic. Furthermore, the addition of a semi-crystalline recycled material in the amorphous matrix (PS) contributed to an increase in thermomechanical strength, as seen in the HDT. The morphology revealed that SEBS is effective in making PS/PPr mixtures compatible because the dispersed phase is well adhered to the PS matrix and promotes greater morphological stability. Thus, it is possible to add value to discarded material and reduce the costs of the final product, which can reduce pollution.