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【答案】应助回帖
ytstiger1226(金币+300, 翻译EPI+1): 非常感谢！看的出来非常用心！ 2011-05-10 20:38:14
The devulcanization reaction of ground tire rubber (GTR) was investigated by the high shear stress from increasing screw rotation speed during melt extruding of the mixture with thermoplastic elastomers (EPDM3745、EPDM4770、POE8150) . Polysulfide, a promoting agent, and the variety of GTR were changed in order to explore the factors.
The gel content, IR and mooney viscosity of devulcanized ground tire rubber (DGTR) were measured.The revulcanized blends of styrene-butadiene rubber (SBR) with DGTR were observed by SEM and the mechanical properties were also characterized.
The results show that the high shear stress can stress-induce the chain scission and cross-link scission, causing the network breakdown.The mechanical properties increased with lower gel content at higher stress . The scission is much more obvious and the gel content decreases by increaseing the screw rotation speed and reaction temperature.
In the equal reaction conditions, the mechanical properties of revulcanized blends DGTR/SBR by ground tire rubber composed by SBR are more excellent than that by natural rubber(NR) or isoprene rubber(IR). The main chain instability of NR and IR made the crosslink easily broken down, leading the low quality on properties of revulcanized blends of DGTR/SBR.
The revulcanized blends of SBR/DGTR/EPDM4770 was investigated by SEM and small gel particles were observed that may caused by low mooney viscosity and low gel content. The SBR/DGTR/EPDM4770 with more preferable microscopic topography and mechanical properties shows better main performance than that of POE8150 and EPDM3745.
The tensile strength and elongation at break of the revulcanized blend SBR/(DGTR/EPDM4770)(70/30) can reach to 20.2 MPa and 521%, which accounted 84.2%, 146% of that of the vulcanized SBR (24.0MPa,356%) respectively when the speed is 1000rpm at 220℃. The promoting agents of polysulfide 420 or 450 can suppress the cross-linking reaction and accelerate the devulcanization during the extruding process with the increase of the tensile strength and elongation at break of the revulcanized blend SBR/(DGTR/EPDM).
Moreover, the polysulfide 450 can further prevent the oxidation ,decomposition and avoid the additive reaction of the double binds in the reaction mixture during the extruding process.
During the devulcanization process of GTR at low temperature or low screw speed, the measurement of quality standards of the mechanical properties of revulcanized DGTR is inappropriate.
The best devulcanization reaction condition can be performed in presence of polysulfide 450 at 220 ℃ when the speed is controlled at 1000 rpm .In that case, the tensile strength and elongation at break of the revulcanized blend SBR/(DGTR/EPDM4770)(70/30) can reach to 21.5 MPa and 639%, which accounted 89.6%, 179% of that of the vulcanized SBR (24.0MPa,356%) respectively.
 看了半天，很多句子有两个谓语，还有不少的中文翻译。尽力了，希望有用。其实真正能将你的文字改好的，是熟悉你这个方向的，我是外行，只能站在英语的角度帮忙了。希望有帮助！ |
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