End-of-Life Tire Destination from a Life Cycle Assessment Perspective

Tires are complex materials manufactured from vulcanized rubber and various other reinforcing materials. One billion end-of-life tires (ELTs) are discarded annually, drawing attention from society. Options for their disposal include reuse, retreading, regeneration, co-processing, pyrolysis, and recycling; however, the ideal alternative has yet to be established. Life cycle assessment (LCA) has been used to quantify their impact and support the decision-making process, in order to determine the most beneficial alternative from an environmental standpoint. Scientific studies on LCA have been carried out on different continents, mainly Europe, Asia, and America. The aim of this chapter was to review studies on the life cycle assessment of end-of-life tire disposal. The main treatment and final destination options were reviewed as well as the most important limitations and aspects of the technologies studied. The most common form of disposal is recycling, with mechanical recycling for use in synthetic grass exhibiting the best environmental performance according to scientific research. Energy recovery also shows good performance, largely due to the emissions prevented through energy conversion. Co-processed and retreaded tires are regularly used for comparison but typically display poor environmental performance in relation to the first two alternatives

Processing and Properties of Plastic Lumber

Plastic residue can be processed into composites using wood flour, mineral fillers, plant or synthetic fibers to obtain plastic lumber, a substitute material for natural wood. The composition and processing conditions are largely responsible for the final characteristics of the plastic lumber. Factors such as density, particle size and moisture content in the material to be processed require extruders with specific technical characteristics, in order to reduce the residence time of the plastic inside the equipment, maintain a constant feed rate and ensure good degassing and homogenization of the components. The composites can be manufactured using single-screw, co- or counter-rotating conical or parallel twin-screw extruders. Plastic lumber exhibits different physical and mechanical properties from natural wood, including lower stiffness (elastic modulus) and superior weathering resistance

Composições de polipropileno heterofásico e borracha EPDM com a incorporação de resíduo de polipropileno e artefatos

DepositadaSão descritas composições de polipropileno heterofásico e borracha EPDM com a incorporação de resíduo de PP na proporção entre 40 e 60% em massa de PP resíduo na composição. As composições são obtidas por extrusão e moldadas em artefatos cujas propriedades mecânicas são avaliadas. Por sua propriedades, as composições da invenção são úteis na indústria automobilística, incluindo a fabricação de para-choques automotivos

Revisão dos tratamentos químicos da fibra natural para mistura com poliolefinas

The use of natural fibers as reinforcement in polymer composites has been a focus of interest. However, these composites exhibit lower mechanical properties than those of pure polymers because of the low interfacial interactions between the hydrophobic polymer matrix and the hydrophilic fiber. To overcome this problem, different chemical treatments applied to the fibers have been reported. One of the most used treatments is mercerization, which can improve adhesion between the fiber and polymeric matrix. Another chemical treatment involves the use of acids (stearic and oleic acids). The chemically treated fibers used in composite materials showed improved mechanical properties

Mixing process influence on thermal and rheological properties of NBR/SiO2 from rice husk ash

Abstract Silica was extracted from rice husk ash (RHA) by a sequence of reactions to produce nanosilica. Two laboratory routes, co-coagulation and spray drying, were used to incorporate the nanosilica into the rubber matrix. Samples were characterized regarding filler incorporation efficiency, thermal stability, rheological behavior and morphology. Thermogravimetric analysis showed that spray-drying was the most efficient filler incorporation process and also the presence of silica increased the thermal resistance of the rubber compound when compared to the unfilled rubber. The rheological behavior showed that NBR filled with silica presented higher elastic torque (S’), storage modulus (G’) and complex viscosity (η*) than unfilled rubber. The Payne effect was also observed for the composites produced by spray-drying. In addition, the thermal behavior and Payne effect results were supported by the comparison of morphology observed by FEG-SEM analysis