Compatibilized thermoplastic elastomers based on highly filled polyethylene with ground tire rubber

Abstract

Thermoplastic elastomers (TPE) based on ground tire rubber (GTR) are good strategies for the circular economy and sustainable development of waste tire rubber recycling. However, several parameters must be optimized to produce valuable TPE. The most important ones are GTR concentration and dispersion, as well as crosslinking degree, combined with interfacial interactions between the GTR and the thermoplastic matrix. In this work, TPE based on highly filled linear low‐density polyethylene (LLDPE) with GTR (50%–90%) was prepared via dynamic vulcanization. In particular, different reclaimed GTR (RR) was used alone or with a compatibilizer (maleic anhydride grafted polyethylene, PE‐g‐MAH) to prepare compatibilized TPE. The interactions between the rubber and plastic were quantified by a series of characterizations including mechanical tests, rheological measurements, differential scanning calorimetry, dynamic mechanical analysis and scanning electron microscopy. The results showed that the mechanical properties and processability decreased with increasing GTR content. Although the interfacial compatibility was improved with a higher GTR reclamation degree, the TPE mechanical properties were still gradually decreasing. To improve on these results, PE‐g‐MAH was added to increase the GTR‐LLDPE interfacial interactions. The results showed improvement in terms of mechanical properties and processability, especially for compatibilized TPE based on RR (tensile strength increased from 3.34 to 4.82 MPa and elongation at break from 91% to 101%).

A Comprehensive Study on the Styrene–GTR Radical Graft Polymerization: Combination of an Experimental Approach, on Different Scales, with Machine Learning Modeling

“…These were defined in terms of three principal conditions, namely the reaction temperature, the peroxyde intiator content and the GTR loading, as shown in Table 1. In particular, an effort was made to avoid limiting the amount of GTR to very low values, as it is often the case in other reported studies [12,36], which would also be coherent with an ultimate objective of maximizing the recycling of end-of-life tires [10] in an eventual industrial realization of the system. In this respect, a GTR loading as high as 70% was tested.…”

“…However, the different structures of the two phases (i.e., the PS matrix and GTR, GTR having the form of a 3D crosslinked network) present a challenge in terms of their compatibility and the resulting poor mechanical properties of the final blend. Accordingly, several compatibilization strategies can be envisioned, such as devulcanization and reclamation or surface activation [2,3,5,6,10,11]. In this work, a chemical surface activation strategy in the form of in situ cross-linking by grafting polymerization, which is among the most prominent GTR surface modification techniques [6], is employed to produce PS-GTR composites.…”

“…Note that, most reported studies are either limited to low GTR loadings (i.e., up to 30% wt.) or concern different polymer matrices and/or compatibilization strategies [10,12,[36][37][38][39][40][41][42]. At the same time, the precision and repeatability of the results are rarely discussed.…”

Cross-Linking, Morphology, and Physico-Mechanical Properties of GTR/SBS Blends: Dicumyl Peroxide vs. Sulfur System

“…The incorporation of modified or unmodified GTR into polymer systems is a topic that has been addressed and studied for many years. GTR is usually added to thermoplastics such as polyethylene (PE) [ 16 , 17 , 18 ], polypropylene (PP) [ 19 , 20 , 21 ], polyvinyl chloride (PVC) [ 22 ], etc. It is also common to create blends based on natural or synthetic rubbers [ 23 , 24 , 25 ].…”

Improving the mechanical properties of vulcanizates containing ground tire rubber: Recipe optimization with the Taguchi method

“…1,[7][8][9][10] However, in most cases, there is poor compatibility between the matrix and the GTR in these new mixtures, resulting in materials that are not suitable for their intended applications. 5,11,12 To address this issue, researchers have developed several compatibility-improving procedures in the past, but these can often be costly (devulcanization) 13 and have a significant environmental impact (chemical treatments). 14 When the GTR is mixed into fresh rubber, optimizing the recipe presents a good, easier, and cost-effective way to adjust various mechanical parameters, 15 which is our goal in this paper.…”