论文部分内容阅读
以乙烯渣油减压蒸馏重组分(ET-HR)为原料,采用溴化/脱溴聚合两步法制备了新型高软化点各向同性沥青,研究了溴化温度和溴引入量对所得产品性质参数的影响.GCMS与LDI TOF/MS测试结果表明,ET-HR主要由富含饱和脂肪侧链的3-6环芳香烃组成.ET-HR分别经30℃和200℃溴化后直接经350℃热处理发生脱溴化氢缩合反应.与简单热缩聚相比,该两步法显著提高了所得沥青的软化点(241 ～ 264℃)、产品得率(62 wt.％～67 wt.％)以及氮气下的残碳率(57 wt.％～77 wt.％).对所得脱溴聚合沥青的组成和结构通过元素分析、1H NMR、FT-IR和LDI-TOF/MS等技术手段进行了表征,结果表明脱溴聚合显著增强了前驱体的芳构化和缩聚反应程度.800℃炭化结果表明,溴化/脱溴聚合两步法所得各向同性沥青能够完全转变为各向异性织构,从而可广泛应用于高级炭材料领域.“,”Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar (ET-HR) by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ET-HR was first brominated at 30 or 200 ℃,and then heat-treated at 350 ℃ to enable the dehydrobromination/polycondensation reactions.GC/MS and LDI TOF/MS spectra indicated that the ET-HR was mainly composed of compounds containing 3-to 6-ring aromatic species with a considerable aliphatic chain content.Compared with thermal condensation alone,such a two-step method increased the softening point of the pitches from 152 to 264 ℃ with a yield in the range of 62 wt.％-67 wt.％ and a coking value in the range of 57 wt.％-77 wt.％,depending on the bromination temperature and the bromine content.Structural characterization of the as-prepared pitches by elemental analysis,1H NMR,FT-IR and LDI-TOF/MS showed increased aromatization and polymerization of the precursor during the dehydrobromination/polycondensation.All the homogeneous isotropic pitches showed an ability to transform into an anisotropic texture after coking at 800 ℃.