共查询到19条相似文献,搜索用时 93 毫秒
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以北宿煤为原料,利用微波选择性加热的特点,考察了微波辐照时间、煤样粒径、NaOH等因素对高硫煤磁性强化磁选脱硫的影响,同时考察了微波-NaOH饱和溶液联合处理对北宿煤磁选脱硫的影响。研究表明,不同粒径的煤样的最大脱硫率存在一个最佳微波辐照时间,而微波-NaOH联合处理法脱硫效果更为显著。对煤样进行微波预处理后,可以根据需要控制NaOH饱和溶液用量达到较为理想的脱硫效果。 相似文献
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以北宿煤为原料,利用微波选择性加热的特点,考察了微波辐照时间、煤样粒径、NaOH等因素对高硫煤磁性强化磁选脱硫的影响,同时考察了微波-NaOH饱和溶液联合处理对北宿煤磁选脱硫的影响.研究表明,不同粒径的煤样的最大脱硫率存在一个最佳微波辐照时间,而微波-NaOH联合处理法脱硫效果更为显著.对煤样进行微波预处理后,可以根据需要控制NaOH饱和溶液用量达到较为理想的脱硫效果. 相似文献
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采用微波联合超声波分别对潞安煤、西山煤、云南煤和阳泉煤进行脱硫研究.考察了氧化剂配比、微波辐照时间、超声波联合微波等条件对煤中有机硫脱除效果的影响.实验结果表明,不同氧化剂配比有不同的脱有机硫效果.其中,V(HAc):V(H2O2)=1∶1时,脱硫效果最佳;微波辐照时间对脱硫率有明显的影响,随着微波辐照时间的延长,有机... 相似文献
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Kohji Masaki Shin‐Ichi Ohkawara Tomohiro Hirano Makiko Seno Tsuneyuki Sato 《应用聚合物科学杂志》2004,91(5):3342-3353
Sulfur‐crosslinked nitrile butadiene rubber (s‐NBR) was found to be devulcanized when it was heated with nitrobenzene at 200°C for 3 h. The tetrahydrofuran (THF)‐soluble fraction from s‐NBR heated with nitrobenzene was purified by reprecipitation with THF/n‐hexane, chloroform/n‐hexane, and THF/n‐hexane systems and was then characterized by means of Fourier transform infrared (FTIR) spectroscopy, 1H‐NMR, gel permeation chromatography, dynamic thermogravimetry/differential thermal analysis (DTA), and differential scanning calorimetry (DSC). FTIR and 1H‐NMR results revealed that the THF‐soluble fraction contained aromatic rings derived from nitrobenzene. Furthermore, the molecular weight of the THF‐soluble fraction was much lower than that of the parent noncrosslinked poly(acrylonitrile‐co‐butadiene). Although the weight loss of THF‐soluble fraction began at a lower temperature than that of the nonheated original nitrile butadiene rubber, the residual weight at 700°C tended to be higher for the former. This tendency became more marked with increasing time of heat treatment with nitrobenzene. The DSC‐determined glass‐transition temperature of the THF‐soluble fraction was higher than that of the original s‐NBR. To elucidate the devulcanization mechanism, we investigated two types of model reactions; one was the reaction of diphenyl disulfide with nitrobenzene, and the other was the reaction of polybutadiene with nitrobenzene. The former reaction, carried out at 250°C in diphenyl ether, yielded diphenyl sulfide with a loss of diphenyl disulfide and nitrobenzene. The use of a higher molar ratio of nitrobenzene to diphenyl disulfide resulted in a depression of diphenyl sulfide formation. The reaction of p‐chloronitrobenzene with diphenyl disulfide also gave diphenyl sulfide. The reaction of polybutadiene with nitrobenzene at 200°C resulted in the backbone scission of the polymer. The THF‐soluble solid product of the latter model reaction was found by FTIR and 1H‐NMR to contain aromatic rings derived from nitrobenzene. The devulcanization mechanism is discussed on the basis of a comparison of the results of the model reactions with those of the s‐NBR devulcanization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3342–3353, 2004 相似文献
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从微波能在非极性硫化橡胶中的转换规律着手,考察了不同的胶种、补强剂和废硫化胶粒径与脱硫时间以及温度的相关性,探讨了这些因素对脱硫胶物理性能和溶胀特性的影响。结果表明,粒径大的硫化胶物料温升速度快;NR硫化胶的温升速度比SBR硫化胶快;炭黑补强硫化胶的温升速度比白炭黑补强硫化胶快。溶胀特性数据表明,NR的脱硫效果优于SBR,硫化胶粒(粒径1~3mm)的脱硫效果优于硫化胶粉(40目和60目);白炭黑补强硫化胶的脱硫效果优于炭黑补强硫化胶 相似文献
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在SBR基轮胎胶(GTR)与三元乙丙橡胶(EPDM)混合物的熔融挤出过程中,采用改变亚临界流体品种和提高螺杆转速的方法,研究了亚临界流体(水,乙醇,丙醇)、螺杆转速、烷基酚多硫化物促进剂(450)以及温度对脱硫共混物(DGTR/EPDM)凝胶含量、门尼粘度、溶胶红外光谱及脱硫共混物共混丁苯橡胶(SBR)再硫化材料(SBR/(DGTR/EPDM))力学性能的影响,对再硫化材料的试样断面形貌也进行了SEM观察。实验结果表明:亚临界流体(水,乙醇,丙醇)作为一种溶胀剂和反应性介质能够很好地促进脱硫反应,提高交联键断裂的选择性,降低脱硫产物的凝胶含量和凝胶颗粒尺寸并明显提高脱硫共混物共混丁苯橡胶再硫化材料的力学性能,其中亚临界乙醇的作用最显著。当450作为一种脱硫促进剂,在最优亚临界乙醇挤出反应条件(200℃,1.6 MPa,600 rpm)下,脱硫共混物共混丁苯橡胶分别达到丁苯生胶混炼硫化材料拉伸强度(24.0MPa)和断裂伸长率(356%)的99.6%和209%。 相似文献
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Influence of reversion in compounds containing recycled natural rubber: In search of sustainable processing 下载免费PDF全文
The influence of rubber devulcanization by microwaves in the reversion behavior is still modestly explored in the literature. The reversion occurs due to thermal degradation of unstable crosslinkings formed during the vulcanization process. This phenomenon results in poor final mechanical properties of the artifacts. In this work, some formulations based on natural rubber (NR) with the incorporation of NR devulcanized by microwaves at different exposure times to the microwaves were vulcanized by compression molding at the same temperature and time used for the study of their vulcanization characteristics, in order to correlate the properties obtained and understand the influence of the reversion on the mechanical properties. The results showed that levels of devulcanization/degradation of the recycled phase, as well as the additional heating time influenced on the behavior of reversion and, consequently, on the mechanical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45325. 相似文献