Insights into PU/EVA Blends Produced Using Industrial Residues Towards Eco-efficient Materials

Abstract

Aiming at minimizing the issues associated with the disposal of polymers, in this study, elastomeric materials derived from 100% recycled feedstocks were produced. Residues of polyurethane (PU) foams (from 0 to 100%) were blended with residues of ethylene-vinyl acetate (EVA) derived from the shoe-soles industry (from 0 to 100%) to produce films by hot compression. The experimental values obtained by the characterization of the blends were compared with the predicted values derived from the rule of mixtures. Despite of the two-phase morphology observed, the high correlation between the experimental and predicted values suggest that phase segregation did not have a significant effect on the properties of the blends. Voids were also observed on the PU derived materials, due to the source of PU (foams), which reduced their density and increased the water absorption. Yet, this did not jeopardize the mechanical performance of the ensuing materials. In addition, higher amounts of PU resulted in stiffer materials, while higher amounts of EVA induced higher thermal stability. From the results, it was demonstrated that the PU/EVA blends, produced from 100% recycled feedstock, presented suitable properties to be used in shoe-soles applications.

A Review of the Plantar Pressure Distribution Effects from Insole Materials and at Different Walking Speeds

“…Some researchers argued that PU has some advantages in its mechanical properties [93,94]. Nonetheless, PU is more expensive than EVA [93,95,96]. Thus, PU could be the multi-insole in part of the plantar region combined with another insole material [41,97].…”

Recycling waste polyurethane from the refrigeration industry as filler inSBR/NRcomposites for industrial applications

“…Figure 10 presents the shoe soles manufactured by Grupo Amazonas®, who incorporated samples of the filled composites formulated here into their production line. The new shoe soles meet the minimum technical requirements for professional and casual footwear 78,79 …”

A Review of Rigid Polymeric Cellular Foams and Their Greener Tannin-Based Alternatives

“…The interest in reusing PUR is such that studies comparing reference PUR foams with recycled PUR foams have been carried out, showing minimal changes in mechanical properties [ 213 ]. Elastomeric materials based on PUR and ethylene vinyl acetate foams with compositions ranging from 0 to 100% recycled resources have also been evaluated, with 100% recycled formulations exhibiting properties suitable for shoe soles [ 214 ]. PUR coatings based on acid-treated PUR waste foams have also been produced, with excellent hydrophobic and mechanical properties [ 211 ].…”