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Investigation of the properties of unidirectional fiber assemblies of single walled carbon nanotube-polyvinyl alcohol composite.

机译：单壁碳纳米管-聚乙烯醇单向纤维组件的性能研究。

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摘要

Carbon nanotubes are difficult to process and this lack of convenient processibility has restricted their use for composite applications. High intensity sonication in surfactant solution has been the most common process used for nanotube exfoliation. Here we utilize our previously reported method to produce continuous SWNT composite fibers having mechanical properties that compare very favorably to recognized man-made or natural so-called "super" fibers such as Kevlar and spider silk. The process involved spinning an exfoliated dispersion of nanotubes into a bath of polyvinyl alcohol (PVA). We further improved our spinning method by using a spinning solution enriched with individual tubes we obtained by ultracentrifugation. The exfoliated state of SWNTs initially present in the spinning solution is preserved in our composite fiber assemblies as monitored using various spectroscopic and microscopic techniques. More importantly, these modifications allowed us to control the final composition and morphology of the assemblies so that the effects of relative concentration and degree of crystallinity on mechanical strength could be investigated. While the interaction between the SWNTs is strictly non-covalent, we find that increasing the accessible surface area of the nanotubes by de-bundling maximizes stress transfer to the polymer matrix, and thus dramatically enhances composite reinforcement. We also correlated the total nanotube surface area with the degree of crystalline domains together with the effects of post-treatment processing. Without employing any fiber treatment, we demonstrated that crystallinity linearly increased with effective nanotube surface area and showed slight improvements in mechanical properties. Moreover, after post-spinning treatments, crystallinity and tensile strength are further increased by factors of 21--40% and 232--437%,respectively. Mechanical drawing was the dominant factor in enhancement of mechanical properties, and is believed to be the effect of further orienting and ordering of both the nanotubes and polymer chains in the fiber. Improvements in crystallinity and overall mechanical properties are seen in fiber composites containing smaller SWNT bundles.
机译：碳纳米管难以加工，并且缺乏方便的加工性能限制了其在复合材料中的使用。表面活性剂溶液中的高强度超声处理已成为用于纳米管剥离的最常用方法。在这里，我们利用我们先前报道的方法生产出具有机械性能的连续SWNT复合纤维，该纤维与公认的人造或天然所谓的“超级”纤维（如凯夫拉尔纤维和蜘蛛丝）相比非常有利。该过程涉及将剥落的纳米管分散体纺丝到聚乙烯醇（PVA）浴中。我们通过使用富含通过超速离心获得的单个试管的纺丝溶液进一步改进了纺丝方法。最初存在于纺丝溶液中的单壁碳纳米管的剥落状态已保存在我们的复合纤维组件中，通过各种光谱学和显微镜技术进行监测。更重要的是，这些修饰使我们能够控制组件的最终组成和形态，从而可以研究相对浓度和结晶度对机械强度的影响。虽然单壁碳纳米管之间的相互作用严格是非共价的，但我们发现通过解束来增加纳米管的可及表面积，可最大程度地将应力转移至聚合物基体，从而显着增强复合材料的增强作用。我们还将总纳米管表面积与晶畴程度以及后处理过程的影响相关联。在不进行任何纤维处理的情况下，我们证明了结晶度随有效的纳米管表面积线性增加，并且机械性能略有改善。此外，在纺丝后处理后，结晶度和拉伸强度分别进一步提高了21--40％和232--437％。机械拉伸是增强机械性能的主要因素，并且据信是进一步使纤维中的纳米管和聚合物链取向和排序的作用。包含较小SWNT束的纤维复合材料的结晶度和整体机械性能得到改善。

著录项

  • 作者

    Razal, Joselito M.;

  • 作者单位

    The University of Texas at Dallas.;

  • 授予单位 The University of Texas at Dallas.;
  • 学科 Engineering Materials Science.; Chemistry Polymer.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 87 p.
  • 总页数 87
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;高分子化学（高聚物）;
  • 关键词

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