Cross polarisation/magic angle spinning 13C-NMR spectroscopic studies of cellulose structural changes in hardwood dissolving pulp process
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Xolani Nocanda
Abstract
Cross polarisation/magic angle spinning 13C NMR spectroscopy has been used to study structural changes in cellulose induced by the dissolving pulp process. The cellulose structure in several dissolving pulps was investigated for commercial and laboratory cooked Eucalyptus 92α and 96α. The average lateral dimension, or average thickness, of the cellulose fibril aggregates is related to the amount of surface area exposed and could be one controlling factor for the chemical reactivity of commercial dissolving pulps during modification reactions. The thickness of the cellulose fibril aggregates governs the amount of surface area present in the fibre wall, and cellulose surface material constitutes the part of the cellulose that is directly accessible to reagents. In all sample series investigated, the raw pulp was found to be less aggregated than the corresponding bleached final pulp. Furthermore, an irreversible increase in fibril aggregate width was observed on free drying for both laboratory cooked and commercial pulps. Upon rewetting with water, the freely dried 96α pulp was found to be more aggregated than the freely dried 92α pulp, although sugar analysis showed very similar carbohydrate compositions. As indicated by the molecular mass distribution, the commercial 92α pulp contained larger amounts of degraded cellulose; this may be a plausible explanation for the different behaviour of the 92α and 96α pulps during free drying.
©2007 by Walter de Gruyter Berlin New York
Articles in the same Issue
- Acknowledgement
- Subject index
- Contents Volume 61 (2007)
- Author index
- Species index (scientific names)
- Meetings
- Improvement of Pinus pinaster Ait elite trees selection by combining near infrared spectroscopy and genetic tools
- Direct method for the determination of phenolic hydroxyl groups in pulp
- Comparative effect of ozone, chlorine dioxide, and hydrogen peroxide on lignin: Reactions affecting pulp colour in the final bleaching stage
- Structural modification of eucalypt pulp lignin in a totally chlorine-free bleaching sequence including a laccase-mediator stage
- Analysis of wood tissues by time-of-flight secondary ion mass spectrometry
- Isolation and identification of residual chromophores from aged bleached pulp samples
- Studies on oxidative modifications of cellulose in the periodate system: Molecular weight distribution and carbonyl group profiles
- Lignin-carbohydrate network in wood and pulps: A determinant for reactivity
- Cross polarisation/magic angle spinning 13C-NMR spectroscopic studies of cellulose structural changes in hardwood dissolving pulp process
- Fungal decay of spruce and beech wood assessed by near-infrared spectroscopy in combination with uni- and multivariate data analysis
- Paper mill sludge as a component of wood adhesive formulation
- Implementation of sorption hysteresis in multi-Fickian moisture transport
- Time/temperature equivalence in the dry wood creep response
- Neural network prediction of bending strength and stiffness in western hemlock (Tsuga heterophylla Raf.)
- Bending properties of particleboard and MDF layers
- Gold as an X-ray CT scanning contrast agent: Effect on the mechanical properties of wood plastic composites
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
Articles in the same Issue
- Acknowledgement
- Subject index
- Contents Volume 61 (2007)
- Author index
- Species index (scientific names)
- Meetings
- Improvement of Pinus pinaster Ait elite trees selection by combining near infrared spectroscopy and genetic tools
- Direct method for the determination of phenolic hydroxyl groups in pulp
- Comparative effect of ozone, chlorine dioxide, and hydrogen peroxide on lignin: Reactions affecting pulp colour in the final bleaching stage
- Structural modification of eucalypt pulp lignin in a totally chlorine-free bleaching sequence including a laccase-mediator stage
- Analysis of wood tissues by time-of-flight secondary ion mass spectrometry
- Isolation and identification of residual chromophores from aged bleached pulp samples
- Studies on oxidative modifications of cellulose in the periodate system: Molecular weight distribution and carbonyl group profiles
- Lignin-carbohydrate network in wood and pulps: A determinant for reactivity
- Cross polarisation/magic angle spinning 13C-NMR spectroscopic studies of cellulose structural changes in hardwood dissolving pulp process
- Fungal decay of spruce and beech wood assessed by near-infrared spectroscopy in combination with uni- and multivariate data analysis
- Paper mill sludge as a component of wood adhesive formulation
- Implementation of sorption hysteresis in multi-Fickian moisture transport
- Time/temperature equivalence in the dry wood creep response
- Neural network prediction of bending strength and stiffness in western hemlock (Tsuga heterophylla Raf.)
- Bending properties of particleboard and MDF layers
- Gold as an X-ray CT scanning contrast agent: Effect on the mechanical properties of wood plastic composites
- Lignin modification in the initial phase of softwood kraft pulp delignification with polyoxometalates (POMs)
