In-Plane Moisture Transport in Paper Detected by Magnetic Resonance Imaging

Leisen, Johannes; Hojjatie, Barry; Coffin, Douglas W.; Beckham, Haskell W.

doi:10.1081/drt-100001361

Cited by 23 publications

(12 citation statements)

References 3 publications

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“…It has previously been observed that moisture invades into nanocellulose films at two different time-scales (Minelli et al, 2010): Fickian diffusion at short time-scales and a slower moisture uptake at long time-scales which may be due to a relaxation of the cellulose matrix (Minelli et al, 2010). It should be mentioned that a similar, two time-scales sorption behavior is observed for ordinary paper, in which case vapor invades through the pore structure and diffuses into denser regions (Leisen et al, 2001;Ramarao et al, 1995), probably best described by dual transport/sorption models for vapor and condensed phase (Ramarao et al, 2003). However, the typical pore size of NFC films is in the order of the mean free path of water molecules in air, which is approximately 68 nm (Jennings, 1988).…”

Section: Through-thickness Moisture Dynamicsmentioning

confidence: 58%

Mechanosorptive creep in nanocellulose materials

et al. 2012

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The creep behavior of nanocellulose films and aerogels are studied in a dynamic moisture environment, which is crucial to their performance in packaging applications. For these materials, the creep rate under cyclic humidity conditions exceeds any constant humidity creep rate within the cycling range, a phenomenon known as mechanosorptive creep. By varying the sample thickness and relative humidity ramp rate, it is shown that mechanosorptive creep is not significantly affected by the through-thickness moisture gradient. It is also shown that cellulose nanofibril aerogels with high porosity display the same accelerated creep as films. Microstructures larger than the fibril diameter thus appear to be of secondary importance to mechanosorptive creep in nanocellulose materials, suggesting that the governing mechanism is found between molecular scales and the length-scales of the fibril diameter.

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Section: Through-thickness Moisture Dynamicsmentioning

confidence: 58%

Mechanosorptive creep in nanocellulose materials

et al. 2012

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“…There were no significant difference in the behaviour in MD and CD, and thus, a mean value over the densities of the CD and MD samples was calculated for further analysis. The decision is supported by Leisen et al, 18 who report that diffusion of moisture in the plane of the sheet is isotropic.…”

Section: Diffusivitiesmentioning

confidence: 81%

“…18 This result was obtained by exposing round test pieces to a step change in relative humidity, and observing the forced convection drying with magnetic resonance imaging. One of the studied materials was polyethylene coated paperboard.…”

Section: In-plane Diffusion Of Moisturementioning

confidence: 99%

Moisture content of polyethylene coated solid fibreboard after industrial lamination

Paunonen

Lenes²,

Gregersen

2011

Packag Technol Sci

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Solid fibreboard is used mainly in highly demanding packaging applications. One solid fibreboard quality having six paper and paperboard layers, a thickness of 1.7 mm and polyethylene coating was studied. Several material tests on liquid water and water vapour penetration were done to assess the environmental moisture sources that change the material moisture content after the lamination process. The in-plane diffusion coefficient of the combined board was determined based on an integrated unsteady state moisture transport equation and moisture sorption measurements. The transverse diffusion coefficient of the polyethylene coated kraft paper and the solid fibreboard medium were based on water vapour transmission rate measurements. The original moisture content of the solid fibreboard sheet was measured gravimetrically 2 days after the lamination at the mill. The results show that high relative humidity (RH) conditions during the transportation (4°C/90% RH) change the moisture content of the transportation box made from a solid fibreboard sheet very little in 8 days. Local moister (or drier) INTRODUCTIONContainerboard is the largest grade group by volume in the paper industry, accounting for 31% (117 million tons) of the world's total paper and board production. 1 Corrugated containers make the majority of packaging production. Solid fibreboard is a multilayer paper-based packaging material often based on recycled fibres. The material can be finished with a variety of lining papers and optionally polyethylene coating. Most grades are glued together in an off-line laminator. Solid fibreboard boxes account for 0.5% of US total industry corrugated shipments.1 Solid fibreboard is mainly used in demanding packaging applications where the product is wet, frozen or greasy. The difference in consumption is reflected in the extent of research done on these materials.Several paperboard layers are glued together in a lamination process to form a solid fibreboard sheet. The glue contains water. The lamination process together with the moisture content of the sheets determines the original moisture content of the laminated paperboard. As a transport box, the sheet is exposed both to liquid water and water vapour. The exposure takes place through the edges and planes of the sheet. Mechanical properties of paper-based materials depend strongly on the moisture content of the material. 2 The strength of the container box is thus dependent on the initial moisture content after production, and how the material resists additional moisture penetration into the material. This work aims at evaluating the effect of different moisture sources in the environment on the moisture content of the sheet when it is used as a transport box. This topic is justified from a practical point of view, since the mechanical properties of the transport box folded from a solid fibreboard sheet depend on the evolvement of the material moisture content during transportation.In the present work, the original moisture content of a newly fabricated solid fib...

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“…Magnetic resonance imaging (MRI) offers one possibility to acquire such data. [75][76][77][78][79] Harding et al [76] achieved a resolution of 15 lm which was sufficient to follow the moisture gradients in a cardboard during drying. Leisen et al [78,79] studied in moisture transport during drying of handsheets and paperboard using a 2 D MRI set-up.…”

Section: Heat and Mass Transfer In The Papermentioning

confidence: 99%

Drying of paper: A review 2000–2018

Stenström

2019

Drying Technology

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Drying of paper during 2000-2018 is reviewed. The review includes new drying processes, multi-cylinder dryers, tissue and impingement drying, TAD-drying, infrared drying and energy use for drying of paper. It includes general aspects of infrared dryers but not drying of coated papers. Paper quality aspects, paper shrinkage and paper isotherms are not included. Impingement drying has been the most successful new technology with several applications while others such as impulse drying has not been commercialized mainly due to problems with paper quality parameters. One promising development is the introduction of steel instead of cast iron cylinders with increased heat transfer reducing the number of cylinders. Future research should focus on modeling the internal transport phenomena and to couple these phenomena to paper shrinkage and quality parameters. The influence of the fabric for the drying process needs more attention, understanding the drying process for new components such as microfibrillar cellulose in the stock and reducing energy use and increasing the amount of renewable energies for drying of paper.

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In-Plane Moisture Transport in Paper Detected by Magnetic Resonance Imaging

Cited by 23 publications

References 3 publications

Mechanosorptive creep in nanocellulose materials

Mechanosorptive creep in nanocellulose materials

Moisture content of polyethylene coated solid fibreboard after industrial lamination

Drying of paper: A review 2000–2018

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