scholarly journals Investigation of the effect of aging on wood hygroscopicity by 2D 1H NMR relaxometry

Holzforschung ◽  
2020 ◽  
Vol 74 (4) ◽  
pp. 400-411 ◽  
Author(s):  
Leila Rostom ◽  
Denis Courtier-Murias ◽  
Stéphane Rodts ◽  
Sabine Care
Keyword(s):  
Cell Walls ◽  
Molecular Level ◽  
Bound Water ◽  
Proton Nuclear Magnetic Resonance ◽  
Wood Material ◽  
H Nmr ◽  
Nmr Relaxometry ◽  
Wood Chemical Composition ◽  
S2 Layer ◽  
1H Nmr Relaxometry

AbstractTwo-dimensional proton nuclear magnetic resonance (2D 1H NMR) relaxometry is increasingly used in the field of wood sciences due to its great potential in detecting and quantifying water states at the level of wood constituents. More precisely, in this study, this technique is used to investigate the changes induced by “natural” and “artificial” aging methods on modern and historical oak woods. Two bound water components are detected and present differences in terms of association to the different wood polymers in cell walls: one is more strongly associated with wood polymers than the other. The evolution of the two bound water types is discussed in regard to aging methods and is related to the structure of the cell wall, especially with the S2 layer and the evolution of wood chemical composition (cellulose, hemicelluloses and lignin). The evolution of hydric strains is also discussed taking into account the effect of aging methods on the two bound water components. The obtained results confirm the ability of 2D 1H NMR relaxometry to evaluate the effect of aging at the molecular level and on hydric deformation. Furthermore, this method shows that it is possible to determine the moisture content of wood without the necessity to oven-dry the wood material.

Combination of solid-state NMR and 1H NMR relaxometry for the study of intercalated saponite clays with the macrocyclic derivatives of Gd(iii) and Y(iii)

2020 ◽  
Vol 49 (20) ◽  
pp. 6566-6571 ◽  
Author(s):  
Daniela Lalli ◽  
Stefano Marchesi ◽  
Fabio Carniato ◽  
Chiara Bisio ◽  
Lorenzo Tei ◽  
...  
Keyword(s):  
Solid State ◽  
1H Nmr ◽  
Solid State Nmr ◽  
Chemical Properties ◽  
H Nmr ◽  
Nmr Relaxometry ◽  
Physico Chemical ◽  
Derivatives Of ◽  
1H Nmr Relaxometry ◽  
Synthetic Saponite

A combination of solid-state NMR and 1H-NMR relaxometric investigations has been employed to characterize the structure and physico-chemical properties of a novel synthetic saponite intercalated with Gd(iii) and Y(iii) chelates.

scholarly journals NMR determination of sorption isotherms in earlywood and latewood of Douglas fir. Identification of bound water components related to their local environment

Holzforschung ◽  
2017 ◽  
Vol 71 (6) ◽  
pp. 481-490 ◽  
Author(s):  
Marie Bonnet ◽  
Denis Courtier-Murias ◽  
Paméla Faure ◽  
Stéphane Rodts ◽  
Sabine Care
Keyword(s):  
Relaxation Times ◽  
Bound Water ◽  
Sorption Isotherms ◽  
Local Environment ◽  
Douglas Fir ◽  
Adsorption Mechanisms ◽  
H Nmr ◽  
Nmr Relaxometry ◽  
Sorption Energy

Abstract Earlywood (EW) and latewood (LW) have different hygromechanical behaviors, if subjected to relative humidity (RH) variations. To understand this effect better, the adsorption mechanisms of EW and LW of Douglas fir were studied by 2D 1H NMR relaxometry under conditions of equilibrium moisture content (EMC) at 20°C. Two bound water components were detected with relaxation times T1 and T2 indicating that they are located in distinct environments but these are similar in EW and LW. Sorption isotherms were calculated and analyzed based on the sorption model of Dent. A difference of sorption energy between the two water components is in agreement with their mobility difference observed on T1−T2 correlation spectra. Moreover, for the two bound water components, EW and LW exhibit different sorption isotherms at high RH. This may be attributed to a difference of adsorption capacity. Based on the macrofibril models provided by the literature, the following hypothesis is proposed: bound water components are located in lamellar and lenticular areas, both leading to possible deformations.

Role of water during AlN-hydrolysis-assisted solidification in ceramic suspensions studied by proton nuclear magnetic resonance T2 relaxation

2003 ◽  
Vol 18 (8) ◽  
pp. 1968-1974 ◽  
Author(s):  
S. Novak ◽  
G. Lahajnar ◽  
A. Sepe ◽  
T. Kosmač
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bound Water ◽  
Proton Nuclear Magnetic Resonance ◽  
Solid Matrix ◽  
Water Proton ◽  
H Nmr ◽  
Hydrolysis Process ◽  
Ceramic Suspensions ◽  
Nuclear Magnetic

Using proton nuclear magnetic resonance (1H-NMR), we have studied the thermally activated hydrolysis of aluminum nitride admixed into Al2O3 aqueous suspensions. We paid special attention to the formation of aluminum hydroxide and its role in binding the host ceramic particles into a stiff solid matrix. The water–proton NMR spin-spin relaxation time (T2) was continuously measured as a function of the time of the AlN hydrolysis in the host Al2O3 ceramic suspension. T2 was found to correlate with an increasing fraction of bound water at the surface of the formed hydrogel and so provided us with information about the gel-surface growth during the hydrolysis process. These results are in good agreement with the observed time- and composition-related increases in high-frequency impedance for the analyzed suspensions.

Probing the Water Phases and Microstructure in a Model Cement Blend Matrix used for the Encapsulation of Intermediate Level Nuclear Wastes

2006 ◽  
Vol 932 ◽  
Author(s):  
Jean-Philippe Gorce ◽  
Neil B. Milestone ◽  
Peter J. Mcdonald
Keyword(s):  
Freeze Drying ◽  
Cement Hydration ◽  
Mercury Intrusion Porosimetry ◽  
Bound Water ◽  
Gravimetric Analysis ◽  
Evaporable Water ◽  
Mercury Intrusion ◽  
H Nmr ◽  
Nmr Relaxometry ◽  
Median Pore

ABSTRACTThe changes in microstructure and content of water phases during hydration of a 3:1 BFS:OPC blend are investigated by Mercury Intrusion Porosimetry (MIP), freeze-drying, Thermal Gravimetric Analysis (TGA) and 1H Nuclear Magnetic Resonance (NMR) relaxometry. MIP indicates that during the blend hydration, a reduction in the population of capillary pores (larger than about 100 nm) occurs while the population of gel pores (smaller than few tens of nanometres) increases. Between 3 and 90 days, the porosity estimated by MIP decreases from about 36% down to 18% while the median pore size decreases from about 140 nm down to 6 nm.1H NMR relaxometry shows that after 1 day of hydration, nearly 70% of the evaporable water is held in capillary pores while about 30% is present in gel pores. After two weeks, most of the evaporable water (90%) is found in pores smaller than few tens of nanometres.The amount of evaporable water detected by freeze drying decreases from less than 20 wt.% after one week of hydration down to about 16.3 wt.% after 90 days while the amount of chemically bound water related to the degree of advancement of the cement hydration and detected by TGA increases from 8 wt.% to 10.3 wt.%.During hydration the BFS:OPC blend matrix evolves from an open microporous network to one of a poorly connected network of water rich nanopores with increasing amounts of chemically bound water.

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