Scholarlink

<p>The drop technique and optical interferometry were applied to examine the morphological formation using “rigid” (water) and “soft” (alcohols and water-solvent mixes) coagulants for PAN solutions in <i>N</i>-methylmorpholine-<i>N</i>-oxide (NMMO). The ideal formulation of the coagulation bath consists of a solvent–coagulant combination of 20–40% NMMO in water. In the course of evolution of optical characteristics of PAN solutions in NMMO at increased temperatures, it was shown that prolonged heating induces alterations in the solution’s color due to the initiation of cyclization of nitrile groups. A dry-jet wet method was used to spin fibers from both “fresh” solutions and those aged at 110&#xa0;°C for one hour. Fibers spun from a fresh solution are pale yellow, whereas those spun from the solution kept at high temperature are brown. Despite the thermal history, the morphology of the spun PAN fibers remains virtually unchanged. X-ray diffraction analysis shows that fibers spun from the aged solution had only a modest reduction in crystallinity, but the size of crystallites rose from 13.5 to 15&#xa0;Å. Measurements of the mechanical properties of the fibers revealed that the key parameters were virtually identical regardless of the solution history. The strength of fibers spun in baths with 20% NMMO-80% water reaches 150&#xa0;MPa, and the relative elongation is up to 149%.Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results indicate that the thermal behavior of fibers obtained immediately before and during thermal holding at 110&#xa0;°C exhibited variability. In particular, the carbon yield for fibers spun from aged solutions decreased.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

The Role of Coagulation and Dope Aging Conditions on Properties of PAN Fibers Obtained from N-Methylmorpholine-N-Oxide Solutions

  • 期刊论文

  • 发表日期：

    2026年3月4日

查看全文
  • Ekaterina E. Palchikova,
  • Igor S. Makarov,
  • Markel I. Vinogradov,
  • Yuriy O. Kulanchikov,
  • Valery G. Kulichikhin

摘要

The drop technique and optical interferometry were applied to examine the morphological formation using “rigid” (water) and “soft” (alcohols and water-solvent mixes) coagulants for PAN solutions in N-methylmorpholine-N-oxide (NMMO). The ideal formulation of the coagulation bath consists of a solvent–coagulant combination of 20–40% NMMO in water. In the course of evolution of optical characteristics of PAN solutions in NMMO at increased temperatures, it was shown that prolonged heating induces alterations in the solution’s color due to the initiation of cyclization of nitrile groups. A dry-jet wet method was used to spin fibers from both “fresh” solutions and those aged at 110 °C for one hour. Fibers spun from a fresh solution are pale yellow, whereas those spun from the solution kept at high temperature are brown. Despite the thermal history, the morphology of the spun PAN fibers remains virtually unchanged. X-ray diffraction analysis shows that fibers spun from the aged solution had only a modest reduction in crystallinity, but the size of crystallites rose from 13.5 to 15 Å. Measurements of the mechanical properties of the fibers revealed that the key parameters were virtually identical regardless of the solution history. The strength of fibers spun in baths with 20% NMMO-80% water reaches 150 MPa, and the relative elongation is up to 149%.Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results indicate that the thermal behavior of fibers obtained immediately before and during thermal holding at 110 °C exhibited variability. In particular, the carbon yield for fibers spun from aged solutions decreased.

Graphical Abstract