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Lars Nordstierna & Åsa Östlund Applied Surface Chemistry Chalmers University of Technology Characterization of cellulose with NMR
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Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Jan 16, 2020

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Page 1: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

Lars Nordstierna & Åsa ÖstlundApplied Surface ChemistryChalmers University of Technology

Characterizationof cellulose with NMR

Page 2: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

EXPERIMENTAL NMR

Direct information

chemical analysis quantitative analysis

NMR SPECTROSCOPY

Page 3: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

EXPERIMENTAL NMR

1) Liquid NMR2) Liquid NMR, Chemical Shift Imaging3) Solid State NMR 13C4) NMR Cryoporometry

NMR SPECTROSCOPY

Page 4: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

Dissolution and Gelation of Cellulose in TBAF/DMSO Solutions: The Roles of Fluoride Ions and Water

Situation:To chemically modify cellulose to reach high yield dissolved cellulose

Cellulose is insoluble in water but soluble in salt‐containing solvents e.g.:LiCl/DMAc (McCormick, Lichatowich, J. Polym. Sci. 1979, 17)TBAF/DMSO (Heinze et al.,Macromol. Chem. Phys. 2000, 201)Ionic liquids, 1‐butyl‐3‐methylimidazolium cation with Cl ‐, Br ‐, SCN – (Swatloski et al., JACS 2002, 124)

Cellulose solutions hygroscopic and transforms into gels in the presence of water

Aim in Paper I:To increase understanding of interactions between cellulose andthe solvent ions, and the impact of water

Method:  NMR Spectroscopy

Liquid NMR I

Page 5: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

19F NMR

-140 -160-120-100

F- HFSiF6-2

19F [ppm]

b)

a)

-140 -160-120-100

F- HFSiF6-2

19F [ppm]

b)

a)

Shift change

Change in the chemical surrounding

Peak broadening

Association to a larger molecule

ORA distribution of 

molecular surroundings

TBAF/DMSO

TBAF/DMSO+ 1% cellulose

Liquid NMR I

Page 6: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

Dissolution and gelation of cellulose in TBAF/DMSO

Elimination of water will increase the effect of F‐electrostatic separation of the cellulose chains

Dissociated salt: small ion will associate to OH‐cellulose Bulky counter ion to reduce the attraction between the ions

Liquid NMR I

Page 7: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

Chemical Shift Imaging NMR to track gel formation

Situation:In many applications hydrogels and transport of molecules in hydrogels

are of interest e.g.:Drugs diffusing through a water‐swollen tabletUrine uptake of diapers

The mass‐transport of the components in the system is dependent on their interaction with the material, the osmotic pressure, and concentration gradients Diffusion coefficient

Aim in Paper II:To monitor multi‐component mass‐transport

Method: 19F and 1H Chemical Shift Imaging

Courtesy of A. Viridén

Liquid NMR II

Page 8: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

GelGelGel GelGel GelGel GelH2O

Liquid NMR II

Page 9: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

H2O Gel

Extract diffusion from the images

D = σ2/2t

Liquid NMR II

Östlund et al, J. Coll. Interface Sci 344 (2010) 238‐240

Page 10: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of TechnologyLars Nordstierna

PAPER PULP 13C SPECTRUM

Solid State NMR I

Page 11: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

PAPER PULP 13C SPECTRUM

Solid State NMR

Page 12: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

Purpose

the effect of regeneration conditions on structural properties

Objective

to study regenerated cellulose with regard to coagulation medium and drying conditions

- pore size distribution (nm-scale)- morphology

PROJECT

Solid State NMR

Page 13: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

Drying

5 conditions (never-dried…->..humidity…->..oven)

Solid characterization

regenerated material

- solid-state NMR spectroscopy- NMR cryoporometry

METHODS

Solid State NMR

Page 14: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of TechnologyLars Nordstierna

PAPER PULP 13C SPECTRUM

Solid State NMR

Page 15: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of TechnologyLars Nordstierna

Morphology

cellulose I (native)

cellulose II (H2O)

amorphous (alcohols)

RESULTS

Solid State NMR I

Page 16: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of TechnologyLars Nordstierna

RESULTS

Solid State NMR I

Page 17: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of TechnologyLars Nordstierna

RESULTSSolid State NMR

Crystallinity

Coagulation media: Water

increased crystallinityupon drying

Page 18: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

RESULTS

Porosity

pore collapseupon drying

-> increased amount of nm-pores

similar behavior for filmscoagulated in all solvents(both crystalline and amorphous films)

NMR cryoporometry

Page 19: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

EXPERIMENTAL NMR

1) Liquid NMR2) Liquid NMR, Chemical Shift Imaging3) Solid State NMR 13C4) NMR Cryoporometry

NMR SPECTROSCOPY

Page 20: Characterization of cellulose with NMR - COST FP1205Characterization of cellulose with NMR. Chalmers University of Technology EXPERIMENTAL NMR Direct information chemical analysis

Chalmers University of Technology

ACKNOWLEDGMENT

Funding

Södra Skogsägarna Foundation for ResearchSP Technical Research Institute of SwedenThe Swedish Research Council Formas

Equipment and Facilities

Forest Products and Chemical Engineering, ChalmersSwedish NMR Centre