Recycling of EPDM rubber via thermomechanical devulcanization: Batch and continuous operations

Dávid Zoltán Pirityi, Tamás Bárány, Kornél Pölöskei

Location

ScienceDirect

Abstract

Thermomechanical devulcanization is a possible solution for the circular economy of EPDM rubber, as it removes covalent crosslinks from vulcanizates, resulting in a material similar to uncured rubber mixes. In this paper, sulfur-cured EPDM rubber was treated with thermomechanical stimuli: a) processing on a two-roll mill and in an internal mixer, and b) twin-screw extrusion. Horikx's analysis indicated a 75 % decrease in crosslink density with little polymer chain degradation. The resulting devulcanizates and non-devulcanized rubber crumb were added to the original rubber mix, yielding samples with 0, 25, 50, 75 and 100 wt% recycled rubber contents. Revulcanizates with up to 50 wt% devulcanizate content retained the tensile strength of the original rubber with a slight increase in modulus. Ultimately, batch devulcanization had the most promising results, and extrusion devulcanization was also more beneficial than using non-devulcanized rubber crumb. Crosslink density and morphological tests also support these findings.

Let's make the use of biobased and recovered raw materials the new standard.

Let's make the use of biobased and recovered raw materials the new standard.

Let's make the use of biobased and recovered raw materials the new standard.