Reclaiming of ground rubber tire by a novel reclaiming agent. I. virgin natural rubber/reclaimed GRT vulcanizates

Abstract

Mechanochemically devulcanized ground rubber tire (GRT) was (re)vulcanized in compositions with virgin natural rubber (NR). The NR/GRT (re)vulcanizates with GRT content from 20 to 60 wt% have been prepared and studied. Reclaiming of GRT was successfully carried out by tetra methyl thiuram disulfide (TMTD) in presence of spindle oil at around ambient temperature. The cure characteristics and mechanical properties of the virgin NR/reclaim GRT blend were studied. The optimum cure time decreases but scorch time remain unaltered with increasing reclaim rubber content in the blend. Effect of carbon black was studied in NR/RR (80/20) blend. Ageing characteristics of different NR/RR blends were evaluated. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the NR/RR vulcanizate. The dynamic mechanical properties and swelling behavior of NR/RR blend vulcanizates were examined. The elastic and storage modulus of the NR/RR vulcanizates become improve with increasing reclaim rubber content. Electrical properties of NR/RR vulcanizates were also studied. POLYM. ENG. SCI., 47:1091–1100, 2007. © 2007 Society of Plastics Engineers

Improving the properties of reclaimed waste tire rubber by blending with poly(ethylene‐co‐vinyl acetate) and electron beam irradiation

“…The k values showed a slight increase with increasing RTR content. Similar observations on n and k values have been reported in the literature , De et al, 2007, Joseph et al, 79 2003, Sujith et al, 2003. These findings suggest that with increasing RTR content; there is increased restriction on the diffusion of toluene molecules into the sample resulting in lower equilibrium uptake and increased interaction between toluene molecules and sample allowing for faster reach to equilibrium.…”

“…However, the mechanical properties of the polymeric matrices, be it rubber, thermoplastic or thermoplastic elastomer; was found to deteriorate with the incorporation of GTR (da Costa and Ramos, 2008, De et al, 2007, Hong and Isayev, 2001. The vulcanized structure of GTR renders the polymeric blend/composite stiff, hence, fails to enhance the properties.…”

Curing characteristics, mechanical properties and morphology of butyl rubber filled with ground tire rubber (GTR)

“…Swelling degree increased with GTR content in butyl vulcanizates, which was due to low cross-linking of butyl rubber matrix (migration of curing system is described under ''cure characteristics'' section) and lowering of cross-linking density of GTR arising from partial devulcanization of GTR. Tetramethylthiuram disulfide accelerator (TMTD) was used as vulcanization accelerator which might have acted as a devulcanization agent for GTR [36][37][38]. According to the published data, increasing time of mixing of GTR with a different range of TMTD accelerator content (1, 5-3, 25 g) was due to higher concentration of sol fraction, lower cross-linking density and Mooney viscosity of the obtained reclaimed rubber.…”

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

“…To further understand the devulcanization mechanism, theoretical relationship developed by Horikx [20] was used, which correlates the rubber soluble fraction of the devulcanizates and the relative decrease in crosslink density. When only main-chain scission takes place, the relative decrease in the apparent crosslink density is given by Equation (6): (6) where S i and S f are the soluble fraction of the untreated vulcanizate and reclaimed vulcanizate respectively, ! i is the crosslink density of the untreated vulcanizate and !…”

“…As a result, a number of physical and chemical methods have been developed to break the crosslink bonds or induce active groups on the surface of ground rubber. These methods are based on mechanical energy [1], ultra-sound [2,3], microwave irradiation [4,5], chemical desulfurization reagents [6,7] or biotechnological methods [8]. Depending on their efficacy, they lead to the devulcanization or the reclaiming process.…”