Poly (Lactic Acid)/Ground Tire Rubber Blends Using Peroxide Vulcanization.

Nicolas Candau,Gero Förster,Noel León Albiter,Maria Lluïsa Maspoch,Oguzhan Oguz

doi:10.3390/polym13091496

Nicolas Candau, Gero Förster + Show 3 more

Open Access

https://doi.org/10.3390/polym13091496

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Abstract

Poly (Lactic Acid) (PLA)/Ground Tire Rubber (GTR) blends using Dicumyl peroxide (DCP) as a crosslinking agent were prepared with the following aims: propose a new route to recycle wastes rubber from the automotive industry and improve the toughness and impact strength of the inherently brittle bio-based PLA. The GTR were subjected to two types of grinding process (cryo- and dry ambient grinding). Swelling measurements revealed the grinding to be associated with a mechanical damage of the rubber chains, independently on the type of grinding or on the GTR size (from <400 µm to <63 µm). Moreover, the finest GTR contains the largest amount of reinforcing elements (carbon black, clay) that can be advantageously used in PLA/GTR blends. Indeed, the use of the finest cryo-grinded GTR in the presence of DCP showed the least decrease of the tensile strength (−30%); maintenance of the tensile modulus and the largest improvement of the strain at break (+80%), energy at break (+60%) and impact strength (+90%) as compared to the neat PLA. The results were attributed to the good dispersion of both fine GTR and clay particles into the PLA matrix. Moreover, a possible re-crosslinking of the GTR particles and/or co-crosslinking at PLA/GTR interface in presence of DCP is expected to contribute to such improved ductility and impact strength.

Highlights

Due to the generation of mega-tons of plastics and rubber wastes each year in Europe, the polymer industry is facing a considerable ecological risk [1]
This study presents an investigation dedicated to the preparation of PLA-Ground Tire Rubber (GTR) blends using dicumyl peroxide (DCP) as a crosslinking agent
(Lactic Acid) (PLA)/Ground Tire Rubber (GTR) blends using crosslinking agent were prepared as a route to recycle wastes rubber from the automotive industry (GTR) and improve the toughness of the bio-based brittle PLA

Summary

Introduction

Due to the generation of mega-tons of plastics and rubber wastes each year in Europe, the polymer industry is facing a considerable ecological risk [1] To tackle this issue, the recycling of wastes rubber [2,3] and the elaboration of bio-based plastics [4,5] have shown a wide development within the last decade. The progressive replacement of fresh rubber by Ground Tire Rubber (GTR) in TPE aims to participate in the circular economy of the automotive industry These blends generally contain a limited quantity of wastes rubber as thermoplastic properties rapidly deteriorate at GTR amounts of 10–20 wt% of GTR [18,19]. The interfacial properties between GTR and the plastic matrix can be drastically improved by reducing the GTR particle size [21,22], by using compatibilizers [22,23,24] and vulcanizing agents [24,25,26] or encapsulating wastes rubber into a fresh rubber phase [17,23]

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