Devulcanization of waste tires using a twin‐screw extruder: The effects of processing conditions

Abstract

During recent decades, for both economic and environmental reasons, recycling of waste tires that are based on SBR/NR has been widely considered. In this study the devulcanization process of the tread section of waste tires was carried out by using a twin‐screw extruder. The effects of barrel temperature and screw speed were investigated. Percent of devulcanization, sol fraction, and curing behavior of devulcanized samples were studied. After the addition of curing agents into the devulcanizates, the general behavior of the rheometry test for rubber compounds was observed. Percent of devulcanization and sol fraction depended on the screw speed and barrel temperature, respectively. The devulcanized samples were formulated with virgin rubber (15/85 wt% ratio) and re‐cured successfully. Tensile strength, elongation at break, compression set, hardness, and resilience were evaluated. It was found that the mechanical properties of the compound containing devulcanizates were slightly inferior to those of the virgin compound. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers

Curing characteristics, mechanical and thermal properties of reclaimed ground tire rubber cured with various vulcanizing systems

“…Therefore, development of research projects focused on new methods of reclamation of GTR [20][21][22] requires better understanding of the impact of vulcanizing systems on the properties of the obtained products.…”

The Role of Carbon Black on Devulcanization of Natural Rubber by Microwaves

“…Devulcanization is a way of providing energy to destroy, total or partially, the three-dimensional network formed during vulcanization 4 . The known methods that use different ways to promote the devulcanization of rubber include thermomechanical, thermo-chemical and mechano-chemical [5][6][7][8][9] , physical (by microwaves 3,[10][11][12][13][14][15][16][17][18][19][20] and ultrasound [21][22][23][24][25][26][27][28][29] ) and biochemical [30][31][32][33] . All of them involve complex transformations that lead to depolymerization, oxidation, and in many cases, the degradation of polymeric chains of rubber, with the consequent reduction on its viscosity 34 .…”

Characterization and properties of LDPE/(ground tire rubber)/crosslinked butyl rubber blends

“…At present, reducing the size in the form of grinding is among the most common of the applied scrap rubber recycling technologies; it consists of mechanical disintegration of the scrap rubber material until the required particle size has been reached. The disintegrated scrap rubber containing high‐quality material can be used, among other things, as filler in thermoplastic compositions , thermoplastic elastomers , and rubber compounds , as well as as an asphalt modifier , a cement modifier , an absorbent , and a substrate used in the processes of pyrolysis and devulcanization . In general, the increased content of ground tire rubber (GTR) in polymer composition results in lower mechanical properties of the obtained products.…”