Thermoplastic elastomers based on recycled high‐density polyethylene, ethylene–propylene–diene monomer rubber, and ground tire rubber

Abstract

High-performance thermoplastic elastomers (TPEs), based on recycled high-density polyethylene (HD-PE R ), olefinic type ethylene-propylene-diene monomer rubber (EPDM), and ground tire rubber (GTR) treated with bitumen, were prepared by using dynamic vulcanization technology, and their structure-property relationships were investigated. It was established that special pretreatment of GTR by bitumen confers outstanding mechanical properties on the resulting TPEs. TPEs, containing GTR pretreated by bitumen, exhibit thermal behavior similar to that of the HDPE R /EPDM basic blend in the temperature region up to about 340°C. Rheological measurements showed that bitumen acts as an effective plasticizer for the GTR-containing TPEs. SEM, DSC, and DMTA results revealed improved adhesion between the particles of GTR treated by bitumen and the surrounding thermoplastic matrix, compared to that of the untreated GTR particles. It was concluded that bitumen acts as an effective devulcanizing agent in the GTR treatment stage. In the following steps of TPE production, bitumen acts simultaneously as a curing agent for the rubber components (EPDM/GTR) and as a compatibilizer for the blend components. GTR-containing TPEs, prepared by extrusion technology, were reprocessed (by passing through the extruder six times) without any observable changes in their tensile properties, thermal stability, and melt viscosity.

Blends of ground tire rubber devulcanized by microwaves/HDPE - Part A: influence of devulcanization process

“…However, these blends have high concentrations of GTR phase (80% in mass), a recycled material, what may have deteriorated the mechanical properties. Grigoryeva et al [53] produced dynamically vulcanized blends using GTR, and in some of the production methods used by the authors, TPVs were also not obtained. According to the authors, in these cases there was not an effective interfacial stress transference between the phases, and not an entanglement of the GTR rubber chains into the surrounding matrix.…”

Thermoplastic elastomers blends based on linear low density polyethylene, ethylene-1-octene copolymers and ground rubber tire

“…Several attempts have been made in order to compatibilize GRT and thermoplastic blends. Reactive and non-reactive compatibilization methods, GRT surface modifications based on acid treatments, UV or gamma irradiation, plasma or corona charge, and new methods for preparation of these blends such as: solid-state shear pulverization and solid state mechanochemical millings have been described in the literature [2,7,8] . The resulting materials present mechanical properties more or less similar to those presented by thermoplastic elastomers.…”

“…Grigoryeva et al [8] prepared thermoplastic elastomers based on recycled high density polyethylene (HDPE), EPDM and GRT treated with bitumen. They concluded that bitumen acts simultaneously as a curing agent for the rubber components (EPDM/GRT) and as a compatibilizer for the blend components.…”

Degradation of non-vulcanized natural rubber renewable resource for fine chemicals used in polymer synthesis

“…Other interesting solution is the devulcanization of the NR to produce lower molar mass products. Many papers and reviews [78][79][80][81] are devoted to reclaiming processes of postconsumer vulcanized rubber, as, for example, ground tire rubber [78][79][80][81][82][83][84][85][86][87] . Specifically about the products of the degradation of the non-vulcanized NR, many applications are already find in the literature, as following.…”