Changes in the hygroscopic behavior of cellulose due to variations in relative humidity

Lovikka, Ville; Rautkari, Lauri; Maloney, Thaddeus

doi:10.1007/s10570-017-1570-9

Cited by 22 publications

(15 citation statements)

References 83 publications

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“…N 2 adsorption measurements on wood-derived pulp fibers reveal a collapsed porous structure after drying, 58,59 and by using solvent exchange, the open porous structure was preserved. 24,60 The specific surface area found by water vapor adsorption in the present study is compared to literature values in Table S1, in accordance with the results.…”

Section: Results and Discussionsupporting

confidence: 87%

Mesoporosity of Delignified Wood Investigated by Water Vapor Sorption

et al. 2019

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Wood represents a highly suitable biobased scaffold for the development of mechanically robust and functional materials. Its functionalizability can be enhanced by means of delignification, resulting in an increase in porosity due to partial or complete removal of lignin and hemicellulose constituents. In this work, the impact of partial and complete delignification on the mesoporous structure is investigated via water vapor sorption isotherms and deuterium exchange. Pore size distributions of wood samples with five different delignification levels were compared to native wood. The derived pore size distributions at the water swollen state reveal an increase in porosity with decreasing lignin content. However, after complete lignin removal, drying causes a nonreversible collapse of the cell wall, which results in reduced porosity.

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Section: Results and Discussionsupporting

confidence: 87%

Mesoporosity of Delignified Wood Investigated by Water Vapor Sorption

et al. 2019

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“…Cellulose-based materials, in this study cellulose acetate, are known for their hygroscopic behavior due to the presence of hydroxyl groups in their chemical structure (Chen et al 2020;Lovikka et al 2018). Cellulose acetate, which shows a sigmoidal behavior for moisture absorption, belongs to the highly hygroscopic material category (Mensitieri and Scherillo 2011).…”

Section: Introductionmentioning

confidence: 99%

Moisture absorption measurement and modelling of a cellulose acetate

2021

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With a view toward the application of highly hygroscopic polymers as a humidity responsive self-actuator, the evaluation of the real time moisture concentration in the material becomes a priority. In this paper, the moisture diffusion process in a cellulose acetate (53.3% of acetylation) has been studied. Membranes of cellulose acetate (thickness within the range 66–200 µm) have been prepared, and the moisture absorption at room temperature and at a different relative humidity (RH within the range 21–53%) has been monitored. An analytical model has been used to describe the observed non-Fickian sigmoidal behavior of moisture diffusion. A relaxation factor (β) of about 0.026 s−1 and a moisture diffusion coefficient (D) of 3.35 × 10–6 mm2/s have been determined. At constant room temperature, the moisture concentration at saturation (Csat) has shown a linear relation with relative humidity. The identified values β, D and Csat of the analytical model have been used as input for the finite element simulation of the non-Fickian diffusion. The reliability of the finite element simulations has been confirmed with a second set of experiments.

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“…1 Hierarchical levels of the cellulose fibre structure. From left to right: molecular visualisation of a layer of cellulose chains (in cellulose I b , hydrogen bond network shown in green), a microfibril, and a bundle of four microfibrils (cross-sections shown in the insets; outermost chains coloured in red, others in grey); followed by scanning electron micrographs of the S2 layer of birch (Lovikka et al 2018) and a whole fibre. The orange and blue scale bars in the micrographs indicate 1 lm and 10 lm, respectively…”

Section: Introductionmentioning

confidence: 99%

Chirality and bound water in the hierarchical cellulose structure

et al. 2019

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The origins of the unique properties of natural fibres have remained largely unresolved because of the complex interrelations between structural hierarchy, chirality and bound water. In this paper, analysis of the melting endotherms for bleached hardwood pulps indicates that the amount of nonfreezing bound water (0.21 g/g) is roughly half of the amount of freezing bound water (0.42 g/g). We link this result to the two smallest constitutive units, microfibrils and their bundles, using molecular dynamics simulations at both hierarchical levels. The molecular water layers found in the simulations correspond quite accurately to the measured amount of non-freezing and freezing bound water. Disorder that results from the microfibril twist and amphiphilicity prevents co-crystallisation, leaving routes for water molecules to diffuse inside the microfibril bundle. Moreover, the simulations predict correctly the magnitude of the right-handed twist at different hierarchical levels. Significant changes in hydroxymethyl group conformations are seen during twisting that compare well with existing experimental data. Our findings go beyond earlier modelling studies in predicting the twist and structure of the microfibril bundle.

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Changes in the hygroscopic behavior of cellulose due to variations in relative humidity

Cited by 22 publications

References 83 publications

Mesoporosity of Delignified Wood Investigated by Water Vapor Sorption

Mesoporosity of Delignified Wood Investigated by Water Vapor Sorption

Moisture absorption measurement and modelling of a cellulose acetate

Chirality and bound water in the hierarchical cellulose structure

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