Hornification?its origin and interpretation in wood pulps

Diniz, J. M. B. Fernandes; Gil, M.H.; Castro, José Adilson de

doi:10.1007/s00226-003-0216-2

Cited by 365 publications

(216 citation statements)

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“…For one thing, completely dried cell walls most likely cannot be fully reconstituted, by rehydration, back into their native rheological condition. The analogous problem is termed "retrogradation" in the chemistry of solubilized polysaccharides and "hornification" in wood pulp fiber technology (Fernandez Diniz et al, 2004).…”

Section: Problems In Stress Relaxation Measurementsmentioning

confidence: 99%

Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

et al. 2010

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Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild type. This may be due to the plant's ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply a method, determination of relaxation spectra, which probes, and can separate, the viscoelastic properties of different cell wall components (i.e. those properties that depend on the elastic behavior of load-bearing wall polymers combined with viscous interactions between them). A computer program, BayesRelax, that deduces relaxation spectra from appropriate rheological measurements is presented and made accessible through a Web interface. BayesRelax models the cell wall as a continuum of relaxing elements, and the ability of the method to resolve small differences in cell wall mechanical properties is demonstrated using tuber tissue from wild-type and transgenic potatoes (Solanum tuberosum) that differ in rhamnogalacturonan I side chain structure.

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Section: Problems In Stress Relaxation Measurementsmentioning

confidence: 99%

Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

et al. 2010

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“…This phenomenon of lower hydroxyl accessibility is well-known for some types of wood pulps and is termed hornification. Disagreement has been reported over its cause (Fernandes Diniz et al 2004), but a possible interpretation of more recent studies is that aggregation of cellulose fibrils due to hemicellulose and lignin removal and/or relocation could be involved (Laivins and Scallan 1996;Langan et al 2014;Pönni et al 2014a). That interactions with water can produce structural changes which are not easily reversed is agreed for smaller sugar molecules.…”

Section: Introductionmentioning

confidence: 99%

Hydroxyl accessibility in wood cell walls as affected by drying and re-wetting procedures

2017

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The first drying of wood cell walls from the native state has sometimes been described as producing irreversible structural changes which reduce the accessibility to water, a phenomenon often referred to as hornification. This study demonstrates that while changes do seem to take place, these are more complex than what has hitherto been described. The accessibility of wood cell wall hydroxyls to deuteration in the form of liquid water was not found to be affected by drying, since vacuum impregnation with liquid water restores the native cell wall accessibility. Contrary to this, hydroxyl accessibility to deuteration by water vapour was found to decrease to different levels depending on the drying conditions. Vacuum drying at 60°C for 3 days reduced the accessibility more than drying for 1 day at 103°C without vacuum. Drying for 3 days at 103°C increased the hydroxyl accessibility compared to 1 day. Moreover, the decrease in hydroxyl accessibility to deuteration by water vapour induced by the first drying could be at least partially erased by subsequent vacuum impregnation with liquid water, indicating reversibility. For the drying of solid, non-degraded wood cell walls the results challenge the often supposed process of hornification, understood as a permanent decrease in hydroxyl accessibility to water.

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“…Drying and pressing introduces an irreversible change in lignocellulosic fibers resulting in a loss of swelling ability of fibers that is also named hornification (Fernandes Diniz et al 2004;Pönni et al 2012;Reeves 1991;Weise 1998;Young 1986). The process of hornification has been divided by Weise (1998) into two different phenomena, called wet and dry hornification.…”

Section: Hornificationmentioning

confidence: 99%

“…Depending on the drying temperature this hornification is only partly reversible by mechanical energy or chemical use. The reaction of hydroxyl and carboxyl groups to H-bonds and/or lactone bridge formation in closed pores and collapsed fibers is still under discussion (Fernandes Diniz et al 2004;Lindström 1986;Lindström and Carlsson 1982;Wang 2006).…”

Section: Hornificationmentioning

confidence: 99%

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Initial wet web strength of paper

Belle

Odermatt

2016

Cellulose

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Despite much research into and development within the complex area of the initial wet web strength of paper, no complete model has yet been developed to describe this property. This type of paper strength is the most important property to ensure an effective paper machine run. Furthermore, the process of strength development in the sheet forming and pressing portion of the process is the basis of the final paper strength. Recent investigations have focused on the surface interactions of fibers on the molecular level. There have also been several innovative findings about fiber swelling and the impact of swelling on the mechanical characteristics of fibers in wet conditions. Overall, progress obtained using new methodologies enables a deeper understanding of the mechanism of strength development. This review discusses these important areas by examining the literature and the authors' own work to obtain a better understanding of the strength development in wet paper webs. This paper highlights that the fiber morphology and the dryness of the wet web have the greatest impact on the strength of the wet web. As fiber sources and machinery are fixed, the fiber water gel is one of the easiest factors to adjust via the process water quality and the use of chemical additives.

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Hornification?its origin and interpretation in wood pulps

Cited by 365 publications

References 10 publications

Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

Hydroxyl accessibility in wood cell walls as affected by drying and re-wetting procedures

Initial wet web strength of paper

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