Microwave devulcanization of ground tire rubber and applicability in SBR compounds

Abstract

Rubber recycling is a major environmental challenge, as their covalently crosslinked structure makes it impossible to reprocess via conventional polymer processing technologies. Devulcanization of rubber waste, whereby crosslinks are selectively broken, may provide a solution, as it allows it to be remolded into new shapes. We used two types of ground tire rubbers (GTRs) for this study; mechanically ground and waterjet‐milled GTRs with different particle sizes. First, we revealed the effects of GTR particle size on the devulcanization process. We examined the sol content of the samples before and after devulcanization with two different microwave ovens, a power‐controlled conventional one, and a temperature‐controlled laboratory oven. In the latter one, heating rate and maximum temperature were controlled. We studied the effects of temperature, atmosphere in which the rubber was treated, heating rate, and holding time at maximum temperature. We prepared styrene‐butadiene rubber‐based rubber compounds containing GTR and optimally devulcanized GTR (dGTR_WJ). The physical and mechanical properties of the samples were assessed. The results indicate that both GTR_WJ and dGTR_WJ have an accelerating and a mildly softening effect on curing and dGTR_WJ has a less significant negative effect on mechanical properties: 15 phr GTR_WJ has the same effect as 45 phr dGTR_WJ. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48351.

Elastomeric Composites Containing SBR Industrial Scraps Devulcanized by Microwaves: Raw Material, Not a Trash

“…Similar results have been observed by some authors, by analyzing the properties of polymeric blends composed of polystyrene/SBR devulcanized by ultrasound [21], and blends composed of EPDM/EPDM-r devulcanized by microwaves [23]. In addition, Simon et al [22] compared the results of elastomeric blends containing SBR/GTR (both devulcanized by microwaves or not) and the blends containing devulcanized GTR that presented improved mechanical results, as discussed previously.…”

“…However, the proposed process is advantageous, considering a reduction in costs. In addition, some authors have used the devulcanization process in recycled rubbers before producing composites or polymeric blends to increase the interaction between the phases due to the better dispersion of the recycled rubber particles in the polymeric matrix, which results in a more refined phases morphology and improvements in the mechanical properties [13,[16][17][18][19][20][21][22].…”

Ground Tire Rubber Modified by Ethylene-Vinyl Acetate Copolymer: Processing, Physico-Mechanical Properties, Volatile Organic Compounds Emission and Recycling Possibility

“…Three-dimensional networks present in rubber goods improve their mechanical properties, chemical resistance, and thermal stability. On the other hand, these excellent performances cause difficulties in waste rubbers management and further recycling [ 1 , 2 , 3 ].…”

Investigating the Impact of Curing System on Structure-Property Relationship of Natural Rubber Modified with Brewery By-Product and Ground Tire Rubber

“…The issue in developing good interactions and compatibility is related to the polar and hydrophilic nature of the bio-filler, contrasting to the non-polar and rather hydrophobic rubber [12]. The problem can be solved through the chemical surface modification of the matrix and/or bio-filler, and/or through the improvement of the miscibility and compatibility between components of the biocomposites by other methods [13][14][15][16].A similar approach can be applied to the incorporation of ground tire rubber (GTR) into a raw rubber matrix [17][18][19][20], which also reduces the cost of the final product. Applying this concept can prevent the problem of the increasing amount of waste rubber, which presents as an added difficulty the existence of a three-dimensional cross-linked structure that makes it more difficult for further processing and recycling [21].Taking into account the advantages of the use of waste fillers (cellulose/lignocellulose-based fillers and GTR), a new strategy to improve the performance properties of biocomposites was considered in this study.…”

“…A similar approach can be applied to the incorporation of ground tire rubber (GTR) into a raw rubber matrix [17][18][19][20], which also reduces the cost of the final product. Applying this concept can prevent the problem of the increasing amount of waste rubber, which presents as an added difficulty the existence of a three-dimensional cross-linked structure that makes it more difficult for further processing and recycling [21].…”