Modelling a continuous devulcanization in an extruder

Abstract

An engineering kinetic model is applied to EPDM devulcanization in an extrusion process. Parameters that were included in the model are crosslink density, devulcanizing agent concentration, time, shear rate, and temperature. The extruder is considered as a series of plug flow and stirred tank reactors. The residence time is calculated using solid flow or liquid flow model, depending on the degree of decrosslinking. The model can accurately predict the decrosslinking degree inside the temperature boundary defined by the applied experimental conditions. Outside this boundary, the effect of chemical degradation on the measured conversion becomes more significant. ᭧

Devulcanization of styrene butadiene rubber by microwave energy: Effect of the presence of ionic liquid

“…The Mooney viscosity of the rubber gives an indication of the relative devulcanization degree. Indeed, more is the degree of devulcanization, lower is the Mooney viscosity [26]. Thus, curves in Figure 14 confirmed the earlier results.…”

Review of the Reclaiming of Rubber Waste and Recent Work on the Recycling of Ethylene–propylene–diene Rubber Waste

“…They are autoclave, 82 microwaves heater, [83][84][85] , ultrasonic reactor, [49][50][51][52][53][54][55]80 twin screw extruder, 86,87 and internal batch mixer. 6,58,59 The analytical methods for testing and characterizing devulcanized rubber waste are: solvent swelling, 88 thermogravimetry analysis (TGA), 64,74,76,78 solid-State H neutron mass spectroscopy (NMR), 93,95-100 differential scanning calorimeter (DSC), 101 atomic absorption spectroscopy, 93,101 inductively coupled plasma atomic emission spectroscopy (ICP-AES), 93,101 inductively coupled plasma optical emission spectroscopy (ICP-OES), 93,101 and elemental analysis which involves the determination of the mass fraction of carbon, hydrogen, nitrogen, 93,101 and heteroatoms (X) (CNHX).…”

“…Figure 1 shows the difference in the molecular structure of virgin raw rubber, vulcanized rubber and devulcanized rubber. 4 The energies required to break monosulfidic C-S , polysulfidic S-S and C-C bonds are 270, 240 and 345 kJ/mol, respectively. 5 Hence, caution should be exercised during devulcanization as much as possible to avoid C-C bonds cleavage.…”

“…6,58,86 Sutanto et al 86 devulcanization. In addition, the devulcanized rubber was obtained continuously at the head of the reactor in the form of strand.…”

Rheological properties of a reclaimed waste tire rubber through high-pressure high-temperature sintering

“…Therefore, the use of waste rubber is usually for secondary raw materials such as for conventional composite where the quality is not the main requirement of the resulted products. In other ways, the waste rubber is utilized for repeat use (re-use and retreading), physical recycling (reclaiming, grinding and surface activation), recovery of base chemicals (pyrolysis, gasification, and hydrogenation) and energy recycling (incineration) [4,5]. Nevertheless, the use of waste rubber for those mentioned strategies is still considered as a non-environmental friendly solution due to the harmful effluence [6].…”