中间相沥青的调制及其大直径炭纤维制备

Preparation of mesophase pitch and its large-diameter carbon fibers

以萘沥青为原料,分别采用常压聚合、加压聚合以及甲苯可溶组分加压聚合3种方式调制中间相沥青,并对制备的3种中间相沥青进行熔融纺丝、氧化稳定化和炭化处理制备大直径(约20μm)炭纤维,再利用相关测试仪器对制得的不同中间相沥青及其炭纤维进行分析和表征。结果表明:相同热处理条件下,加压聚合制备的中间相沥青较常压聚合的沥青液晶相转化程度高,分子取向优异,以其为原料制备的大直径炭纤维拉伸强度为840 MPa,明显高于常压聚合沥青所制炭纤维的拉伸强度(540 MPa)。萘沥青经甲苯抽提后灰分从790×10^(-6)降至180×10^(-6),以其可溶组分加压聚合制备的中间相沥青光学织构取向较好,所制大直径炭纤维的拉伸强度可达950 MPa。

Mesophase pitches were prepared from naphthalene pitches by 3 different ways including normal-pressure and pressurized polymerization of naphthalene pitches,and pressure polymerization of toluene soluble component.Various large diameter carbon fibers about 20μm were prepared by melt-spinning,stabilization and carbonization treatments from the synthesized 3 types of mesophase pitches.The obtained mesophase pitches and their carbon fibers were characterized in terms of structure and performance.The results showed that under the same heat treatment condition,both the content and transformation of liquid crystalline of the mesophase pitch prepared by the pressurized polymerization are better than those of the mesophase pitches derived from the normalpressure polymerization,and the molecular arrangement and orientation of the former is anticipated well.The tensile strength of carbon fibers resulted from the pressure-polymerized mesophase pitches is 840 MPa,which is significantly higher than that of the latter(540 MPa).The ash content of toluene soluble component extracted from the naphthalene pitch decreases from 790×10-6 to 180×10-6.Mesophase pitches prepared by pressure polymerization of the toluene soluble component under the same conditions show good optically oriented texture,and the tensile strength of corresponding carbon fibers is up to 950 MPa.