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Raman spectra of celluloses.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Raman spectra of celluloses./
作者:	Wiley, James Hugh.
面頁冊數:	1 online resource (197 pages)
附註:	Source: Dissertations Abstracts International, Volume: 49-11, Section: B.
Contained By:	Dissertations Abstracts International49-11B.
標題:	Chemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=8805210click for full text (PQDT)
ISBN:	9798206285963

Raman spectra of celluloses.
Wiley, James Hugh.

Raman spectra of celluloses. - 1 online resource (197 pages)

Source: Dissertations Abstracts International, Volume: 49-11, Section: B.

Thesis (Ph.D.)--The Institute of Paper Chemistry, 1986.

Includes bibliographical references

A Raman microprobe was used to investigate the vibrational spectra of celluloses. The objectives were to further assign the bands in the vibrational spectrum of cellulose; study the structural differences between cellulose polymorphs; and study molecular orientation in cellulose fibers. The long-term goal of this work is to establish a basis for the use of vibrational spectroscopy in the study of plant cell wall architecture. Several series of spectra in which the polarization of the incident light was varied relative to the fiber axis were recorded from oriented fibers. Analysis of band intensities as a function of polarization revealed information about the directional character of the vibrational motions. A study of deuterated celluloses identified the modes which involve OH and CH motions. This study, together with normal coordinate analyses of model compounds performed by previous researchers, enabled us to identify the types of vibrational motions responsible for most of the bands. The motions identified in this manner agree qualitatively in most cases with traditional group frequency assignments, but the vibrational motions are much more complex. Therefore, this novel approach provides a more thorough characterization of the Raman spectrum of cellulose and establishes a basis for future studies of native tissues. Structural differences between cellulose polymorphs were studied by comparing the spectra of Valonia (predominantly Iα), ramie (predominantly Iβ), and mercerized ramie (II) celluloses. The spectra indicate that celluloses Iα and Iβ have similar molecular conformations, but have distinct hydrogen bonding patterns. In cellulose II, the molecular conformation as well as the hydrogen bonding pattern differs from those in native cellulose. Cellulose orientation in the plane perpendicular to the chain axis was studied by varying the polarization of the incident light relative to the cell wall surface of ramie cross-sections. The results indicate that the cellulose is oriented randomly in the lateral direction perpendicular to the chain axis. In addition, a comparison of spectra from freely-dried and tension-dried cotton fibers indicated that the cellulose was oriented randomly in the lateral direction in freely-dried fibers, but nonrandomly in tension-dried fibers.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798206285963Subjects--Topical Terms:

516420
Chemistry.
Index Terms--Genre/Form:

542853
Electronic books.

Raman spectra of celluloses.
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100 1 $a Wiley, James Hugh. $3 3698506
245 1 0 $a Raman spectra of celluloses.
264 0 $c 1986
300 $a 1 online resource (197 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 49-11, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
502 $a Thesis (Ph.D.)--The Institute of Paper Chemistry, 1986.
504 $a Includes bibliographical references
520 $a A Raman microprobe was used to investigate the vibrational spectra of celluloses. The objectives were to further assign the bands in the vibrational spectrum of cellulose; study the structural differences between cellulose polymorphs; and study molecular orientation in cellulose fibers. The long-term goal of this work is to establish a basis for the use of vibrational spectroscopy in the study of plant cell wall architecture. Several series of spectra in which the polarization of the incident light was varied relative to the fiber axis were recorded from oriented fibers. Analysis of band intensities as a function of polarization revealed information about the directional character of the vibrational motions. A study of deuterated celluloses identified the modes which involve OH and CH motions. This study, together with normal coordinate analyses of model compounds performed by previous researchers, enabled us to identify the types of vibrational motions responsible for most of the bands. The motions identified in this manner agree qualitatively in most cases with traditional group frequency assignments, but the vibrational motions are much more complex. Therefore, this novel approach provides a more thorough characterization of the Raman spectrum of cellulose and establishes a basis for future studies of native tissues. Structural differences between cellulose polymorphs were studied by comparing the spectra of Valonia (predominantly Iα), ramie (predominantly Iβ), and mercerized ramie (II) celluloses. The spectra indicate that celluloses Iα and Iβ have similar molecular conformations, but have distinct hydrogen bonding patterns. In cellulose II, the molecular conformation as well as the hydrogen bonding pattern differs from those in native cellulose. Cellulose orientation in the plane perpendicular to the chain axis was studied by varying the polarization of the incident light relative to the cell wall surface of ramie cross-sections. The results indicate that the cellulose is oriented randomly in the lateral direction perpendicular to the chain axis. In addition, a comparison of spectra from freely-dried and tension-dried cotton fibers indicated that the cellulose was oriented randomly in the lateral direction in freely-dried fibers, but nonrandomly in tension-dried fibers.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Chemistry. $3 516420
650 4 $a Physical chemistry. $3 1981412
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0494
690 $a 0485
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a The Institute of Paper Chemistry. $3 3698507
773 0 $t Dissertations Abstracts International $g 49-11B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=8805210 $z click for full text (PQDT)