Accessibility of cellulose: Structural changes and their reversibility in aqueous media

Pönni, Raili; Kontturi, Eero; Vuorinen, Tapani

doi:10.1016/j.carbpol.2012.12.025

Cited by 43 publications

(27 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(Suchy et al 2010a), this study finds that no or close to no hydroxyls are made inaccessible upon vacuumdrying at 60°C if re-protonation is done with liquid water. Reversibility has previously been reported for cellulosic pulps, but only for alkaline conditions (Pönni et al 2013(Pönni et al , 2014b. Therefore, this is the first study to report nearly full reversibility of deuteration after first drying of native state wood.…”

Section: Hydroxyl Accessibility To Liquid D 2 Omentioning

confidence: 49%

“…Before and after each conditioning period, the dry sample mass was determined by using the built-in heating coil for increasing the temperature locally to 60°C for 6 h followed by a 1 h thermal stabilisation period, both while purging with dry nitrogen gas. Only one conditioning step was applied since it was found that the determined accessibility depends on time of exposure and not on the number of repeated conditioning cycles as has also been reported by others (Pönni et al 2013). Furthermore, previous experiments using longer times of conditioning had shown that the employed conditioning duration was sufficient for providing full deuteration of the accessible hydroxyls.…”

Section: Methodsmentioning

confidence: 77%

See 1 more Smart Citation

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

2017

View full text Add to dashboard Cite

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.

show abstract

Section: Hydroxyl Accessibility To Liquid D 2 Omentioning

confidence: 49%

Section: Methodsmentioning

confidence: 77%

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

2017

View full text Add to dashboard Cite

show abstract

“…For instance, the following studies showed that alkaline conditions used in the repulping of fibers then can promote easier swelling during refining, thus leading to higher strength (Szwarcsztajn and Pryzybysz 1976;Klungness and Caulfield 1982;Guest and Voss 1983;Bhat 1991;Gurnagul 1995;Ogden 1999). Pönni et al (2013) found evidence that alkaline conditions can re-open pore surfaces within fibers that previously had been closed due to drying. Gurnagul observed benefits from alkaline processing of recycled fibers in the case of thermomechanical pulp (TMP); no such benefits were observed when similar treatments were applied to low-yield recycled fibers.…”

Section: Alkaline Processingmentioning

confidence: 98%

Prospects for Maintaining Strength of Paper and Paperboard Products While Using Less Forest Resources: A Review

Hubbe¹

2013

BioResources

View full text Add to dashboard Cite

Paper production requires large amounts of cellulosic fiber, whereas the world's forested lands and croplands have a finite capacity to supply such resources. To deal with likely future pressure on forest resources, as well as to hold down costs of materials, publications examined in the preparation of this review suggest that the paper industry will need to implement several concurrent strategies. In particular, the industry can be expected to view recycling as a central part of its activities. Basis weights of various paper-based products can be expected to decrease over the coming decades, and more of the fiber content will be replaced with fillers such as calcium carbonate. Such trends will place intense demands upon chemical-based strategies to enhance the bonding within paper and paperboard. Based on the literature, further progress in reducing the amount of new forest resources used to meet a given set of paper product requirements will require a combined approach, taking into account various fiber attributes, nanostructures, novel concepts in bond formation, and advances in the unit operations of papermaking.

show abstract

“…In general, it is advisable to use at least three but preferably more replicates for each sample batch due to measurement uncertainties. Only one conditioning stage in D 2 O vapour is needed as the determined accessibility depends on time of exposure and not on number of repeated conditioning cycles (Pönni et al 2013). Moreover, the carrier gas (often nitrogen) should be dried out before the gas (Becker et al 1969).…”

Section: Automated Sorption Balancesmentioning

confidence: 99%

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

2017

View full text Add to dashboard Cite

Water plays a central role in wood research, since it affects all material properties relevant to the performance of wood materials. Therefore, experimental techniques for characterising water within wood are an essential part of nearly all scientific investigations of wood materials. This review focuses on selected experimental techniques that can give deeper insights into various aspects of water in wood in the entire moisture domain from dry to fully water-saturated. These techniques fall into three broad categories: (1) gravimetric techniques that determine how much water is absorbed, (2) fibre saturation techniques that determine the amount of water within cell walls, and (3) spectroscopic techniques that provide insights into chemical wood-water interactions as well as yield information on water distribution in the macro-void wood structure. For all techniques, the general measurement concept is explained, its history in wood science as well as advantages and limitations.

show abstract

Accessibility of cellulose: Structural changes and their reversibility in aqueous media

Cited by 43 publications

References 23 publications

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

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

Prospects for Maintaining Strength of Paper and Paperboard Products While Using Less Forest Resources: A Review

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

Contact Info

Product

Resources

About