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Investigation of the properties of u...

Razal, Joselito M.

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

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Investigation of the properties of unidirectional fiber assemblies of single walled carbon nanotube-polyvinyl alcohol composite./
作者:	Razal, Joselito M.
面頁冊數:	87 p.
附註:	Source: Dissertation Abstracts International, Volume: 66-05, Section: B, page: 2772.
Contained By:	Dissertation Abstracts International66-05B.
標題:	Engineering, Materials Science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3176114
ISBN:	9780542147029

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

Investigation of the properties of unidirectional fiber assemblies of single walled carbon nanotube-polyvinyl alcohol composite. - 87 p.

Source: Dissertation Abstracts International, Volume: 66-05, Section: B, page: 2772.

Thesis (Ph.D.)--The University of Texas at Dallas, 2005.

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.

ISBN: 9780542147029Subjects--Topical Terms:

1017759
Engineering, Materials Science.

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