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

2012 ◽  
Vol 128 (4) ◽  
pp. 2307-2318 ◽  
Author(s):  
Hu Si ◽  
Tianju Chen ◽  
Yuncan Zhang
Keyword(s):  
Shear Stress ◽  
High Shear ◽  
Twin Screw Extruder ◽  
High Shear Stress ◽  
Screw Extruder ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Twin Screw

The influence of feed rate and shear forces on the devulcanization process of ground tire rubber (GTR) conducted in a co-rotating twin screw extruder

Polimery ◽  
2013 ◽  
Vol 58 (11/12) ◽  
pp. 906-912 ◽  
Author(s):  
KRZYSZTOF FORMELA ◽  
MAGDALENA CYSEWSKA ◽  
JOZEF HAPONIUK ◽  
ANDRZEJ STASIEK
Keyword(s):  
Feed Rate ◽  
Twin Screw Extruder ◽  
Shear Forces ◽  
Screw Extruder ◽  
Tire Rubber ◽  
Ground Tire Rubber ◽  
Twin Screw

scholarly journals Best Practice for De-Vulcanization of Waste Passenger Car Tire Rubber Granulate Using 2-2′-dibenzamidodiphenyldisulfide as De-Vulcanization Agent in a Twin-Screw Extruder

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1139
Author(s):  
Hans van Hoek ◽  
Jacques Noordermeer ◽  
Geert Heideman ◽  
Anke Blume ◽  
Wilma Dierkes
Keyword(s):  
Best Practice ◽  
Chain Scission ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Passenger Car ◽  
Tire Rubber ◽  
Twin Screw ◽  
Styrene Butadiene

De-vulcanization of rubber has been shown to be a viable process to reuse this valuable material. The purpose of the de-vulcanization is to release the crosslinked nature of the highly elastic tire rubber granulate. For present day passenger car tires containing the synthetic rubbers Styrene-Butadiene Rubber (SBR) and Butadiene Rubber (BR) and a high amount of silica as reinforcing filler, producing high quality devulcanizate is a major challenge. In previous research a thermo-chemical mechanical approach was developed, using a twin-screw extruder and diphenyldisulfide (DPDS) as de-vulcanization agent.The screw configuration was designed for low shear in order to protect the polymers from chain scission, or uncontrolled spontaneuous recombination which is the largest problem involved in de-vulcanization of passenger car tire rubber. Because of disadvantages of DPDS for commercial use, 2-2′-dibenzamidodiphenyldisulfide (DBD) was used in the present study. Due to its high melting point of 140 °C the twin-screw extruder process needed to be redesigned. Subsequent milling of the devulcanizate at 60 °C with a narrow gap-width between the mill rolls greatly improved the quality of the devulcanizate in terms of coherence and tensile properties after renewed vulcanization. As the composition of passenger car tire granulate is very complex, the usefulness of the Horikx-Verbruggen analysis as optimization parameter for the de-vulcanization process was limited. Instead, stress-strain properties of re-vulcanized de-vulcanizates were used. The capacity of the twin-screw extruder was limited by the required residence time, implying a low screw speed. A best tensile strength of 8 MPa at a strain at break of 160% of the unblended renewed vulcanizate was found under optimal conditions.

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