Effective thermomechanical devulcanization of ground tire rubber with a co-rotating twin-screw extruder

Simon, Dániel Ábel; Bárány, Tamás

doi:10.1016/j.polymdegradstab.2021.109626

Cited by 28 publications

(19 citation statements)

References 37 publications

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“…Research trends showed that low-temperature devulcanization is gaining more and more attention [17][18][19]. The main advantages of low-temperature devulcanization are related to limited main chain scission (the devulcanization mechanism is preferable) and also to significantly reduced levels of volatile organic compounds formulated during rubber reclaiming [20].…”

Section: Introductionmentioning

confidence: 99%

Processing, Performance Properties, and Storage Stability of Ground Tire Rubber Modified by Dicumyl Peroxide and Ethylene-Vinyl Acetate Copolymers

2021

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In this paper, ground tire rubber was modified with dicumyl peroxide and a variable content (in the range of 0–15 phr) of ethylene-vinyl acetate copolymers characterized by different vinyl acetate contents (in the range of 18–39 wt.%). Modification of ground tire rubber was performed via an auto-thermal extrusion process in which heat was generated during internal shearing of the material inside the extruder barrel. The processing, performance properties, and storage stability of modified reclaimed ground tire rubber were evaluated based on specific mechanical energy, infrared camera images, an oscillating disc rheometer, tensile tests, equilibrium swelling, gas chromatography combined with a flame ionization detector, and gas chromatography with mass spectrometry. It was found that the developed formulas of modified GTR allowed the preparation of materials characterized by tensile strengths in the range of 2.6–9.3 MPa and elongation at break in the range of 78–225%. Moreover, the prepared materials showed good storage stability for at least three months and satisfied processability with commercial rubbers (natural rubber, styrene-butadiene rubber).

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Section: Introductionmentioning

confidence: 99%

Processing, Performance Properties, and Storage Stability of Ground Tire Rubber Modified by Dicumyl Peroxide and Ethylene-Vinyl Acetate Copolymers

2021

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“…The crosslinking index was obtained through equation 8, considering the numerical average molecular weight of the NR polymer of 200,000 g.mol -1 , according to the literature [18,19]. Based on the proximity of the curve (random or selective), it is possible to infer whether the dominant phenomenon during the mechanochemical process is more selective or random [18,24]. Selectivity can be done using a coefficient (K).…”

Section: Resultsmentioning

confidence: 99%

Mechanochemical Treatment in High-Shear Thermokinetic Mixer an Alternative for Tire Recycling

Bianchi¹,

Pereira²,

Ferreira³

2022

Preprint

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This publication highlights the effect of mechanochemical treatment in a high-speed thermoki-netic mixer as an alternative for recycling ground tire rubber (GTR). The GTR initially has an 80% gelled fraction and presented up to 50% gel fraction in the most intensive condition (5145 rpm, s2). Processing at the lowest speed (2564 rpm, s1) resulted in greater selectivity concerning the mechanochemical treatment (K~1). In the most intense processing condition (10 min. at s2), more significant degradation was observed via random scission with a reduction of the glass transition temperature, Tg (11ºC), an increase of the soluble polymer fraction, and a more signif-icant reduction in crosslink density. The artificial neural network could describe and correlate the thermal degradation profile and processing conditions with the physicochemical characteris-tics of the GTR. The approach presented here represents an alternative for mechanochemical treatment since it can reduce the crosslink density with selectivity and in short times (1-3 min.).

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“…The Flory–Higgins polymer–solvent interaction parameter χ 12 is a measure of the interaction energy of solvent molecules with rubber, and it can be estimated using Equation (6) [ 36 , 37 , 38 , 39 ].

where β represents the lattice constant for the polymer–solvent system ( β = 0.34), R is the universal constant of gases, T is the absolute temperature, σ r and σ s describe the solubility parameter of the rubber sample and solvent, respectively [ 40 ].…”

Section: Methodsmentioning

confidence: 99%

Mechanical Properties and Equilibrium Swelling Characteristics of Some Polymer Composites Based on Ethylene Propylene Diene Terpolymer (EPDM) Reinforced with Hemp Fibers

Stelescu

Airinei²,

Bargan³

et al. 2022

Materials

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EPDM/hemp fiber composites with fiber loading of 0–20 phr were prepared by the blending technique on a laboratory electrically heated roller mill. Test specimens were obtained by vulcanization using a laboratory hydraulic press. The elastomer crosslinking and the chemical modification of the hemp fiber surface were achieved by a radical reaction mechanism initiated by di(tert-butylperoxyisopropyl)benzene. The influence of the fiber loading on the mechanical properties, gel fraction, swelling ratio and crosslink degree was investigated. The gel fraction, crosslink density and rubber–hemp fiber interaction were evaluated based on equilibrium solvent-swelling measurements using the Flory–Rehner relation and Kraus and Lorenz–Park equations. The morphology of the EPDM/hemp fiber composites was analyzed by scanning electron microscopy. The water absorption increases as the hemp fiber loading increases.

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Effective thermomechanical devulcanization of ground tire rubber with a co-rotating twin-screw extruder

Cited by 28 publications

References 37 publications

Processing, Performance Properties, and Storage Stability of Ground Tire Rubber Modified by Dicumyl Peroxide and Ethylene-Vinyl Acetate Copolymers

Processing, Performance Properties, and Storage Stability of Ground Tire Rubber Modified by Dicumyl Peroxide and Ethylene-Vinyl Acetate Copolymers

Mechanochemical Treatment in High-Shear Thermokinetic Mixer an Alternative for Tire Recycling

Mechanical Properties and Equilibrium Swelling Characteristics of Some Polymer Composites Based on Ethylene Propylene Diene Terpolymer (EPDM) Reinforced with Hemp Fibers

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