NMR studies of wood and wood products

Maunu, Sirkka Liisa

doi:10.1016/s0079-6565(01)00041-3

Cited by 162 publications

(86 citation statements)

References 91 publications

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“…In addition, charcoal is present in many modern soils and sediments, comprising ~30% of the total organic carbon in some Australian and US soils (Skjemstad et al, 1996;2002). This abundance and apparent environmental recalcitrance makes charcoal a crucial source of palaeoenvironmental and archaeological proxy data, used to reconstruct records of fire history, human societal and climate change (Carcaillet et al, 2002, Gavin et al, 2002Goebel et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…In living plants, distinct differences in stable carbon isotopic composition (δ 13 C) arise between those using the Calvin-Benson (or C 3 ) photosynthetic pathway, (typical δ 13 C of -20 to -30‰), and those using the Hatch-Slack (or C 4 ) pathway (typical δ 13 C of -10 to -15‰) (Ehrlinger et al, 1997;2002). Plant δ 13 C is strongly influenced by the ratio of intercellular to ambient CO 2 , and is modulated by factors of soil moisture status, relative humidity, irradiance and temperature (McCarroll and Loader, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Influence of production variables and starting material on charcoal stable isotopic and molecular characteristics

Ascough

Bird

Wormald

et al. 2008

Geochimica et Cosmochimica Acta

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We present a systematic study on the effect of starting species, gas composition, temperature, particle size and duration of heating upon the molecular and stable isotope composition of high density (mangrove) and low density (pine) wood. In both pine and mangrove, charcoal was depleted in δ 13 C relative to the starting wood by up to 1.6‰ and 0.8‰ respectively. This is attributed predominantly to the progressive loss of isotopically heavier polysaccharides, and kinetic effects of aromatization during heating. However, the pattern of δ 13 C change was dependant upon both starting species and atmosphere, with different structural changes associated with charcoal production from each wood type elucidated by Solid State 13 C Nuclear Magnetic Resonance Spectroscopy. These are particularly evident at lower temperatures, where variation in the oxygen content of the production atmosphere results in differences in the thermal degradation of cellulose and lignin. It is concluded that production of charcoal from separate species in identical conditions, or from a single sample exposed to different production variables, can result in significantly different δ 13 C of the resulting material, relative to the initial wood. These results have implications for the use of charcoal isotope composition to infer past environmental change.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of production variables and starting material on charcoal stable isotopic and molecular characteristics

Ascough

Bird

Wormald

et al. 2008

Geochimica et Cosmochimica Acta

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“…Wood is well suited to this approach because it gives 13 C solid-state NMR spectra that are rich in structural information (Haw et al 1984;Newman and Hemmingson 1990;Hult et al 2000;Maunu 2002). Bardet et al (1986) were able to obtain spatial information on wood polymers from 13 C spin diffusion experiments, but this approach is only practical if 13 C-enriched wood is available.…”

Section: Introductionmentioning

confidence: 99%

Spatial relationships between polymers in Sitka spruce: Proton spin-diffusion studies

Altaner¹,

Apperley²,

Jarvis³

2006

Holzforschung

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The spatial arrangement of polymers in Sitka spruce (Picea sitchensis) was investigated by NMR proton spindiffusion studies, supplemented by deuterium-exchange experiments monitored by FTIR spectroscopy. The FTIR spectra of earlywood sections after vapour-phase exchange with deuterium oxide showed that 43% of the hydroxyl groups were accessible to deuteration. This value is lower than predicted in the absence of aggregation of cellulose microfibrils into larger units, but greater than the predicted level of deuteration if 3.5-nm microfibrils surrounded by hemicellulose sheaths were aggregated into 4=4 arrays without space for deuterium oxide to penetrate between the microfibrils. The rate of proton spin diffusion between lignin and cellulose was consistent with the presence of microfibril arrays with approximately these dimensions and with lignin located outside them, in both earlywood and latewood. Proton spin-diffusion data for hemicelluloses were complicated by difficulties in assigning signals to glucomannans and xylans, but there was evidence for the spatial association of one group of hemicelluloses, including acetylated glucomannans, with cellulose surfaces, while another group of hemicelluloses was in spatial proximity to lignin. These data are consistent with a number of nanoscale models for the Sitka spruce cell wall, including a model in which glucomannans are associated with microfibril surfaces within the aggregate and water can penetrate partially between these surfaces, and one in which all non-cellulosic polymers and water are excluded from the interior of each microfibril aggregate.

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“…This non-destructive technique is well adapted to samples with restricted solubility, e.g., residual lignin, or when a physical structure such as cellulose morphology is being studied (Gil and Neto, 1999;Maunu, 2002). The CPMAS 13 C NMR spectra of the modern and peatified woods are shown in Fig.…”

Section: Cpmas 13 C Nmrmentioning

confidence: 99%

“…The resonances of the carbohydrate components in both modern and fossil woods are at 64, 67, 72, 85, 90 and 106 ppm (Gilardi et al, 1995;Maunu, 2002). The Florennes and Onhaye fossil samples have 13 C NMR spectra dominated by a peak related to carbohydrates at 72 and 106 ppm, indicating that the samples are well preserved and retain much of the cellulose present in the lignocellulose structure.…”

Section: Cellulose Structurementioning

confidence: 99%

Physicochemical and biochemical characterization of non-biodegradable cellulose in Miocene gymnosperm wood from the Entre-Sambre-et-Meuse, Southern Belgium

Lechien¹,

Rodriguez²,

Ongena³

et al. 2006

Organic Geochemistry

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Specimens of Miocene fossil wood from the Entre-Sambre-et-Meuse karsts (southern Belgium) were examined using physicochemical and biochemical techniques in order to understand the reasons for the exceptional preservation of these fossilized remains after 15 million years. Structural and chemical changes were assessed by comparing the structural features of the fossil samples with those of their modern counterpart, Metasequoia. Solid state 13Cnuclear magnetic resonance (NMR) and microscopic analysis showed good preservation of the cellulose structure in the fossil wood from the Florennes peat deposit. Despite the substantial cellulose fraction available in the fossil tissue, an enzymatic degradation test and a biochemical methane potential assay showed that the fossil cellulose could not be degraded by cellulases and anaerobic microorganisms usually involved in the biodegradation of organic matter. Moreover, the cellulose structure (crystallinity and surface area) seemed to have no effect on cellulose biodegradability in these Miocene fossil wood samples. On the basis of our observations, we suggest that the presence of a modified lignin structure could greatly influence cellulose preservation/biodegradability.

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NMR studies of wood and wood products

Cited by 162 publications

References 91 publications

Influence of production variables and starting material on charcoal stable isotopic and molecular characteristics

Influence of production variables and starting material on charcoal stable isotopic and molecular characteristics

Spatial relationships between polymers in Sitka spruce: Proton spin-diffusion studies

Physicochemical and biochemical characterization of non-biodegradable cellulose in Miocene gymnosperm wood from the Entre-Sambre-et-Meuse, Southern Belgium

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