沥青前驱体氧形态对其沥青与炭纤维性能的影响（英文）

Effect of the oxygen content and the functionality of spinnable pitches derived from ethylene tar by distillation on the mechanical properties of carbon fibers

以乙烯焦油分别在200、250、300℃常压蒸馏所制基本沥青为原料,采用空气吹扫法制备了相应的各向同性可纺沥青(P200AT,P250AT和P300AT),经炭化后制备了相应的炭纤维。通过元素分析、族组分、TG-MS、FT-IR、^(13)C-NMR、XRD和SEM等手段对沥青和纤维进行了相应的分析表征,探究了沥青的氧化行为,以及沥青前驱体氧形态对其沥青纺丝性能和炭纤维结构性能的影响规律。结果表明:不同蒸馏温度所制沥青具有不同的物性特征,显示出不同的氧化特性。P250AT的软化点、炭收率、含氧量和甲苯不溶物含量均高于其他两种沥青。FT-IR和^(13)C-NMR表明P250AT沥青前驱体的氧形态主要以C=O形式存在,且含量高于P200AT和P300AT。由于沥青前驱体引入了氧化交联所形成的氧分子结构抑制了沥青纤维在预氧化过程中氧的增量,从而减弱了纤维在低温炭化过程中气体的释放,提升了炭纤维的力学性能。因此,P250AT所制沥青基炭纤维表现出较高的拉伸强度(980 MPa)。

Three basic pitches were prepared by the distillation of ethylene tar at 200,250,or 300 ℃ for 3 h.Spinnable pitches were produced from them using air-blowing followed by heat treatment at 330 ℃ for 4 h and are designated P200AT,P250AT and P300AT,respectively.These three pitches,and stabilized fibers and carbon fibers produced from them were characterized by TG-MS,FT-IR,13C-NMR,XRD,SEM,solubility tests and elemental analysis.The components and oxidation reactivity of the basic pitches,and its influence on the oxygen functionality and microstructures of the spinnable pitches and mechanical properties of the resulting carbon fibers were investigated.Results showed that with increasing distillation temperature the aliphatic carbon content and n-hexane and toluene solubility of the basic pitches decreased,while their aromaticity and planarity increased,and the oxidation reactivity reached a maximum at 250 ℃.Of the three spinnable pitches P250AT had the highest softening point,highest carbon yield,oxygen content,and CO content and the highest toluene insoluble fraction.However,the oxygen uptake of P250AT pitch fibers during stabilization was the lowest among the three.This led to a reduction of gas release during carbonization,and therefore the highest carbon yield,the smallest number of defects,the highest tensile strength and the lowest Young’s modulus of all the carbon fibers.