Comparative analysis of ultrasonically devulcanized unfilled SBR, NR, and EPDM rubbers

Yun, Jushik; Isayev, A. I.; Kim, Seok H.; Tapale, M.

doi:10.1002/app.11741

Cited by 31 publications

(21 citation statements)

References 21 publications

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“…Figure 3 shows the ultrasonic power consumption and pressure at the entrance to the devulcanization zone during the devulcanization of butyl rubber at a flow rate of 1 g/s, a gap of 0.5 mm, and a die exit opening of 29.2 mm. As observed for other rubbers,14, 26 the power consumption increased with the increase in the ultrasonic amplitude, and the die pressure decreased with the increase in the ultrasonic amplitude. This was explained as the combined effect of the softening of rubber due to devulcanization, the reduction in friction between rubber particles and the horn surface, and an increasing material temperature at the treatment zone due to ultrasonic vibration 13…”

Section: Resultssupporting

confidence: 71%

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Continuous ultrasonic devulcanization of unfilled butyl rubber

Feng¹,

Isayev²

2004

J of Applied Polymer Sci

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ABSTRACT:The devulcanization of resin-cured unfilled butyl rubber with a grooved-barrel ultrasonic reactor under various processing conditions was carried out. The experiments indicated that, because of the lower unsaturation and good thermal stability of butyl rubber, its devulcanization could be successfully accomplished only under severe ultrasonic-treatment conditions. Gel permeation chromatography measurements were carried out for the virgin gum and sol part of devulcanized samples to study the changes in the rubber network during the devulcanization process. The obtained data showed a significant molecular weight reduction and a broadening of the molecular weight distribution upon devulcanization, which indicated that the devulcanization and degradation of butyl rubber occurred simultaneously. The rheological properties showed that devulcanized butyl rubber was more elastic than the virgin gum.The vulcanizates of the devulcanized butyl rubber showed mechanical properties comparable to those of the virgin vulcanizate. The thermal behaviors of the virgin and devulcanized butyl rubber were different and were correlated to the double-bond content. The structural characteristics of the devulcanized butyl rubber were simulated with the Dobson-Gordon theory of rubber network statistics. A fairly good agreement between the experimental data and theoretical prediction was achieved. The simulation of devulcanized butyl rubber indicated that the rate of crosslink rupture was much higher than that of the main chain.

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Section: Resultssupporting

confidence: 71%

“…The virgin vulcanizate and revulcanized samples had higher T g 's than the corresponding virgin gum and devulcanized samples. Clearly, the glass‐transition temperatures of butyl rubber increased upon crosslinking because of the reduced mobility of the chains, as typically observed for other rubbers 26…”

Section: Resultsmentioning

confidence: 53%

Continuous ultrasonic devulcanization of unfilled butyl rubber

Feng¹,

Isayev²

2004

J of Applied Polymer Sci

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“…Table 3 shows 4 Gel fraction of devulcanised NR as function of cycles of mechanochemical milling 14 who reported that after the NR vulcanisate has been devulcanised through ultrasonic devulcanisation process, an increase of 4uC in T g value could be observed. They ascribed the increase to the transformation of polysulfidic cross-links into cyclic sulphidic structures chemically linked to the backbone chain during ultrasonic treatment, which leads to the decrease in the mobility of chains.…”

Section: Thermal Propertiesmentioning

confidence: 99%

Devulcanisation of natural rubber vulcanisate through solid state mechanochemical milling at ambient temperature

Zhang¹,

Lu²,

Liang³

2007

Plastics, Rubber and Composites

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The devulcanisation of natural rubber (NR) vulcanisate was carried out with the self-designed pan mill type mechanochemical reactor that can exert fairly strong shearing force on the milled materials. The experimental results indicate that gel fraction of the devulcanised NR is substantially reduced, and the reduction of molecular weight of the sol part of devulcanised NR is not significant. The mechanical properties of the revulcanised NR increase with increasing milling cycle. After mechanochemical milled 30 cycles, the tensile strength increased to 7?1 MPa, which is about 60% of that of the virgin NR vulcanisate. Elongation at break as high as 973?0% was obtained, which is the same as that of the virgin NR vulcanisate. Solid state mechanochemical milling is a simple, low cost method for the devulcanisation of cross-linked rubber vulcanisates at ambient temperature without the use of any chemicals and is feasible to be industrialised.

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“…Most of the recycling processes are based on the devulcanization of the material, which can mainly be achieved through physical and chemical processes. 3 Among the most used types of physical processes are: mechanical, 4,5 thermo-mechanical, [6][7][8][9][10][11] ultrasonic, [12][13][14][15][16] and microwave. [17][18][19][20][21] In the chemical process different organic amines, [22][23][24] disulfides, 25,26 mercaptans, 27 and inorganic systems [28][29][30] have been intensively studied.…”

Section: Introductionmentioning

confidence: 99%

Investigation of new composite materials based on activated EPDM rubber waste particles by liquid polymers

Lepadatu

Asaftei²,

Vennemann

2015

J of Applied Polymer Sci

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Despite of the variety of existing techniques, there is still a continuous demand in the development of more efficient recycling technologies, for economic and environmental reasons. A new approach for recycling EPDM rubber waste has been recently introduced utilizing a solvent free activation process by addition of liquid polymers (LP). The present study investigates the influence of the content and varying types of activated rubber waste particles (RWP-LP) in new composites. By varying the proportion of RWP-LP in the range from 25 up to 75 v/v % information about optimized compositions of new compounds were obtained. It was found that the ratio and type of RWP-LP induce significant differences in terms of cure characteristics, mechanical properties, crosslink density and morphology. Promising results with high potential application for the production of seal and sealing systems on the industrial scale were obtained by using up to 50 v/v % of RWP-LP with low ethylene amount.

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Comparative analysis of ultrasonically devulcanized unfilled SBR, NR, and EPDM rubbers

Cited by 31 publications

References 21 publications

Continuous ultrasonic devulcanization of unfilled butyl rubber

Continuous ultrasonic devulcanization of unfilled butyl rubber

Devulcanisation of natural rubber vulcanisate through solid state mechanochemical milling at ambient temperature

Investigation of new composite materials based on activated EPDM rubber waste particles by liquid polymers

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