中间相沥青熔融纺制异形纤维的研究

用热缩聚和催化缩聚两种不同工艺制备的中间相沥青及自行设计的五种喷丝板,熔融纺制出中空、条形、Y 形和圆形截面的沥青纤维。实验证明,沥青熔体的出口膨胀性是影响异形纤维特别是中空纤维纺丝成形的重要流变学参数。这一参数随中间相沥青的性质和熔体温度而变化,在较高温度下,沥青熔体的出口膨胀性减小,使得所纺制异形纤维截面的异形度降低。X 射线衍射分析结果表明,不同形状的喷丝板因其不同的当量直径,在纺丝时对熔体产生不同的剪切作用;当量直径越小,剪切作用越强,沥青分子沿纤维轴的取向度越高,因此可使其炭纤维的力学性能提高。

Melt-spinning of non-circular fibers from mesophase pitches

Hollow, ribbon, Y-shaped and circular pitch fibers were spun from thermally and catalytically condensed mesophase pitches by using five self-designed spinnerets. It was proven in the experiment that the die-swell of molten pitch is an important rheological parameter affecting the formation of non-circular, especially hollow fibers. This parameter changes along with the properties and the melt temperature of mesophase pitch. At relatively higher temperature, the die-swell of molten pitch became smaller, and then the non-circular degree of cross-section of the spun fibers decreased. It was known from X-ray diffraction analysis that the different shaped spinnerets, with different hydraulic diameters, exerted different shear actions on the pitch melt during the spinning. The smaller the hydraulic diameter, the stronger the shear action exerted, resulting in the increase of the orientation of the pitch molecules along the axis direction and then the mechanical properties of the carbon fibers obtained.