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Synchrotron x-ray and neutron fiber diffraction studies of cellulose polymorphs.

DE2001783559

Publication Date	2001
Personal Author	Langan, P. A.
Page Count	7
Abstract	We are determining the precise crystal structures and hydrogen-bonding systems of naturally occurring and processed cellulose polymorphs by fiber diffraction. X-rays are used to determine the positions of carbon and oxygen atoms. Neutrons, in combination with isotopic substitution of labile hydrogen atoms in the fibers by deuterium, are used to determine the positions of hydrogen atoms involved in hydrogen bonding. Methods have been developed for obtaining oriented polycrystalline fibers that diffract X-rays and neutrons to atomic resolution. For the first time, data have been collected from naturally occurring pure cellulose I(alpha) isolated from Glaucocystis (a microalgae) and from pure cellulose I(beta) isolated from Tunicate (a sea creature). We have also collected data from the polymorphs resulting from cellulose processing; II (both mercerized and regenerated), III(I) and III(II).
Keywords	Cellulose X-ray diffraction Neutron diffraction Crystal structure Hydrogen bonds Fibers Synchrotron radiation
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	46 - Physics
Corporate Authors	Los Alamos National Lab., NM.; Department of Energy, Washington, DC.
Document Type	Conference Proceedings
NTIS Issue Number	200208
Contract Number	W-7405-ENG-36

Synchrotron x-ray and neutron fiber diffraction studies of cellulose polymorphs.

Synchrotron x-ray and neutron fiber diffraction studies of cellulose polymorphs.
DE2001783559

Publication Date	2001
Personal Author	Langan, P. A.
Page Count	7
Abstract	We are determining the precise crystal structures and hydrogen-bonding systems of naturally occurring and processed cellulose polymorphs by fiber diffraction. X-rays are used to determine the positions of carbon and oxygen atoms. Neutrons, in combination with isotopic substitution of labile hydrogen atoms in the fibers by deuterium, are used to determine the positions of hydrogen atoms involved in hydrogen bonding. Methods have been developed for obtaining oriented polycrystalline fibers that diffract X-rays and neutrons to atomic resolution. For the first time, data have been collected from naturally occurring pure cellulose I(alpha) isolated from Glaucocystis (a microalgae) and from pure cellulose I(beta) isolated from Tunicate (a sea creature). We have also collected data from the polymorphs resulting from cellulose processing; II (both mercerized and regenerated), III(I) and III(II).
Keywords	Cellulose X-ray diffraction Neutron diffraction Crystal structure Hydrogen bonds Fibers Synchrotron radiation
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	46 - Physics
Corporate Authors	Los Alamos National Lab., NM.; Department of Energy, Washington, DC.
Document Type	Conference Proceedings
NTIS Issue Number	200208
Contract Number	W-7405-ENG-36