Toward the reuse of styrene–butadiene (SBRr) waste from the shoes industry: production and compatibilization of BioPE/SBRr blends

• Published in: Polymer bulletin (Berlin, Germany) Germany), 2024, Vol.81 (11), p.10311-10336
• Main Authors: Alves, Lindemberg Martins Ferreira, Luna, Carlos Bruno Barreto, de Matos Costa, Anna Raffaela, da Silva Barbosa Ferreira, Eduardo, do Nascimento, Emanuel Pereira, Araújo, Edcleide Maria
• Format: Article
• Language: English
• Subjects: Butadiene; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Circular economy; Compatibility; Complex Fluids and Microfluidics; Consumption; Copolymers; Crystallization; Elongation; Footwear industry; Hardness; Impact strength; Injection molding; Landfill; Melt flow index; Modulus of elasticity; Morphology; Organic Chemistry; Original Paper; Physical Chemistry; Plastic deformation; Polyethylene; Polymer blends; Polymer Sciences; Processing industry; Raw materials; Rubber; Scanning electron microscopy; Soft and Granular Matter; Styrenes; Tensile strength; Thermal stability; Thermodynamic properties; Thermogravimetry; Twin screw extruders
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-024-05181-5

The postconsumer waste of vulcanized styrene–butadiene rubber (SBRr) is a raw material rich in additives with potential reuse in the plastics processing industry. The present investigation evaluated the effectiveness of styrene–ethylene/butylene–styrene copolymer (SEBS) in the compatibilization of biopolyethylene (BioPE)/SBRr blends. The blends were processed in a twin-screw extruder and injection molded to evaluate the melt flow index (MFI), impact strength, tensile strength, Shore D hardness, thermogravimetry (TG), differential scanning calorimetry (DSC), and heat deflection temperature (HDT). Morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The BioPE/SBRr/SEBS blend (70/20/10 wt%) showed the lowest MFI, which indicates a higher viscosity and, consequently, higher compatibility that led to increments of 120% and 698.6% on impact strength and elongation at break, respectively, compared to the noncompatibilized system. The reduction in elastic modulus, tensile strength, and Shore D hardness confirmed the increased flexibility of the BioPE/SBRr/SEBS blends. Melting and crystallization properties of the polymer blends were comparable to the BioPE matrix, suggesting that 20 wt% SBRr content did not severely deteriorate the thermal behavior. SEM analysis showed that SEBS induced a morphology with extensive plastic deformation, confirming the high impact strength and elongation at break. BioPE/SBRr blends compatibilized with SEBS offer significant technological potential, indicating that SBRr can be introduced into the productive chain and contribute to sustainability.