Ultrasonic devulcanization of carbon black–filled ethylene propylene diene monomer rubber

Abstract

ABSTRACT:The recycling of carbon black (CB)-filled ethylene propylene diene monomer (EPDM) rubber was carried out by using a newly built continuous ultrasonic groovedbarrel reactor. Using this reactor, it was possible to increase by two times the output of devulcanized rubber in comparison with the coaxial reactor built earlier. The dynamic viscoelastic properties of virgin vulcanizates, devulcanized, and revulcanized EPDM rubbers were measured. The cure behavior of virgin and devulcanized rubbers was measured. The gel fraction and crosslink density of virgin vulcanizate and devulcanized EPDM rubbers, and the mechanical properties of virgin vulcanizates and revulcanized rubbers were determined. Similar to our previous findings using the coaxial reactor, the revulcanizates of unfilled EPDM rubbers of the present study showed higher mechanical properties than those of the virgin unfilled vulcanizates. However, a progressive decrease in the mechanical properties of CB-filled EPDM revulcanizates with an increase of filler concentration, attributed to partial deactivation of filler, was observed. An improvement of mechanical properties of vulcanizates was achieved upon blending the devulcanized and virgin filled rubbers.

Continuous devulcanization of waste tires by using a Co‐rotating twin screw extruder: Effects of screw configuration, temperature profile, and devulcanization agent concentration

“…The advantages of this approach in comparison with other devulcanization methods are continuity, high speed, and higher efficiency. The quality of devulcanized rubber obtained through this method is affected by processing conditions such as temperature profile, screw rotation speed, and screw configuration [2,[12][13][14][15][16][17][18].…”

Effects of high shear stress on the devulcanization of ground tire rubber in a twin‐screw extruder

“…Some studies38–51 have also shown that ultrasonic oscillations degrade the polymer melt and greatly enhance the compatibility and mechanical properties of high‐density polyethylene (HDPE)/EPDM, HDPE/polystyrene (PS), polypropylene (PP)/EPDM, and PP/NR blends through the chain scission of the blends and the coupling of the long‐chain radicals and effectively initiate the functionalization reaction of HDPE and EPDM with maleic anhydride to prevent the crosslinking reaction.…”

Optimization and effect of 3‐aminopropyltriethoxysilane content on the properties of bentonite‐filled ethylene propylene diene monomer composites

“…Carbon black (CB) had been top ranked and extensively used as reinforcing filler to enhance the mechanical properties of numerous rubber compounds. However, recent debates on the pollution issue, high cost, dark color, and health awareness due to CB usage have aroused a significant amount of interest in the developments of other types of reinforcing materials such as silica, calcium carbonate, and clay minerals [2–9].…”