Water vapor sorption dynamics in different compressions of eelgrass insulation

Eelgrass shows potential in meeting the rising demands towards new, sustainable materials. It hosts a range of characteristics that benefits its application as a building material, such as thermal and acoustic insulating properties that can compete with conventional mineral wool insulation. However, as a porous bio-based building material, the moisture performance of eelgrass must be assessed to ensure its practical application. In this study, experimental investigations are conducted by a new automated vapor sorption analyzer (VSA) to measure adsorption and desorption of water vapor on different compressions of eelgrass insulation, ranging from loose strands to densely compacted insulation batts. Overall, higher sorption dynamics are observed in eelgrass insulation compared to conventional mineral wool insulation. Loose strands of eelgrass depict higher dynamics (including hysteresis) for the full range of relative humidity in comparison to insulation batts, potentially due to additional binder. Increasing the compression of eelgrass insulation batts results in lower sorption dynamics in the >70% relative humidity range. A Guggenheim-Anderson-deBoer model is applied that shows good fit with the experimental data and may be applied in moisture transfer calculations. This study furthers the potential of compressing eelgrass for application in passive design strategies through its moisture buffering capabilities.

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Effects of acetylation and formalization on the dynamic water vapor sorption behavior of wood

Holzforschung ◽

10.1515/hf-2014-0161 ◽

2015 ◽

Vol 69 (5) ◽

pp. 633-643 ◽

Cited By ~ 31

Author(s):

Sarah Himmel ◽

Carsten Mai

Keyword(s):

Cell Wall ◽

Water Vapor ◽

Relative Humidity ◽

Water Vapor Sorption ◽

Cross Linking ◽

Sorption Behavior ◽

Matrix Stiffness ◽

Vapor Sorption ◽

Dynamic Vapor Sorption ◽

Cell Wall Polymers

Abstract The dynamic water vapor sorption of untreated, acetylated (Wac), and formaldehyde-treated (WFA) Scots pine (Pinus sylvestris L.) sapwood was studied in a dynamic vapor sorption apparatus to assess the effects of cell wall bulking and cross-linking. Both modifications resulted in a considerable reduction of reduced equilibrium moisture content (EMCR), the corresponding equilibrium times, and hysteresis in the hydroscopic range of wood. Acetylation reduced the adsorption and desorption of water at each given relative humidity (RH) step from 0% to 95% RH, whereas formalization affected the sorption behavior of wood solely above 20% RH. From 20% to 95% RH, the EMC ratio of WFA to its control steadily decreased, whereas the EMC ratio of Wac was still constant in this RH range. Below 20% RH, the sorption behavior of Wac was governed by hydroxyl blocking, whereas that of WFA was hardly influenced compared with the control. Above 20% RH, the sorption behavior of Wac was solely determined by cell wall bulking, whereas that of WFA was governed by the increased matrix stiffness due to the cross-linking of cell wall polymers.

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Determining the Critical Relative Humidity at which the Glassy to Rubbery Transition Occurs in Polydextrose Using an Automatic Water Vapor Sorption Instrument

Journal of Food Science ◽

10.1111/j.1750-3841.2010.01884.x ◽

2010 ◽

Vol 76 (1) ◽

pp. E78-E89 ◽

Cited By ~ 26

Author(s):

Xiaoda Yuan ◽

Brady P. Carter ◽

Shelly J. Schmidt

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Water Vapor Sorption ◽

Vapor Sorption ◽

Critical Relative Humidity

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Use of Ramping and Equilibrium Water Vapor Sorption Methods to Determine the Critical Relative Humidity at which the Glassy to Rubbery Transition Occurs in Polydextrose

Journal of Food Science ◽

10.1111/j.1750-3841.2010.01968.x ◽

2011 ◽

Vol 76 (1) ◽

pp. E149-E157 ◽

Cited By ~ 9

Author(s):

Qingruisi E. Li ◽

Shelly J. Schmidt

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Water Vapor Sorption ◽

Vapor Sorption ◽

Critical Relative Humidity

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Water sorption on coal: effects of oxygen-containing function groups and pore structure

International Journal of Coal Science & Technology ◽

10.1007/s40789-021-00424-6 ◽

2021 ◽

Author(s):

Ang Liu ◽

Shimin Liu ◽

Peng Liu ◽

Kai Wang

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Photoelectron Spectroscopy ◽

Isosteric Heat ◽

Water Vapor Sorption ◽

Moisture Loss ◽

Isotherm Model ◽

Water Molecules ◽

Vapor Sorption ◽

Adsorption Stage

AbstractCoal-water interactions have profound influences on gas extraction from coal and coal utilization. Experimental measurements on three coals using X-ray photoelectron spectroscopy (XPS), low-temperature nitrogen adsorption and dynamic water vapor sorption (DVS) were conducted. A mechanism-based isotherm model was proposed to estimate the water vapor uptake at various relative humidities, which is well validated with the DVS data. The validated isotherm model of sorption was further used to derive the isosteric heat of water vapor sorption. The specific surface area of coal pores is not the determining parameter that controls water vapor sorption at least during the primary adsorption stage. Oxidation degree dominates the primary adsorption, and which togethering with the cumulative pore volume determine the secondary adsorption. Higher temperature has limited effects on primary adsorption process.The isosteric heat of water adsorption decreases as water vapor uptake increases, which is found to be close to the latent heat of bulk water condensation at higher relative humidity. The results confirmed that the primary adsorption is controlled by the stronger bonding energy while the interaction energy between water molecules during secondary adsorption stage is relatively weak. However, the thermodynamics of coal-water interactions are complicated since the internal bonding interactions within the coal are disrupted at the same time as new bonding interactions take place within water molecules. Coal has a shrinkage/swelling colloidal structure with moisture loss/gain and it may exhibit collapse behavior with some collapses irreversible as a function of relative humidity, which further plays a significant role in determining moisture retention.

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Water Sorption on Coal: Effects of Oxygen Containing Function Groups and Pore Structure

10.21203/rs.3.rs-127358/v1 ◽

2020 ◽

Author(s):

Ang Liu ◽

Shimin Liu ◽

Peng Liu ◽

Kai Wang

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Photoelectron Spectroscopy ◽

Isosteric Heat ◽

Water Vapor Sorption ◽

Moisture Loss ◽

Isotherm Model ◽

Water Molecules ◽

Vapor Sorption ◽

Adsorption Stage

Abstract Coal-water interactions has profound influences on gas extraction from coal and coal utilization. Experimental measurements on three coals using X-ray photoelectron spectroscopy (XPS), low-temperature nitrogen adsorption and dynamic water vapor sorption (DVS) were conducted. A mechanism-based isotherm model was proposed to estimate the water vapor uptake at various relative humidities, which was well validated with the DVS results. The validated isotherm model of sorption is further used to derive the isosteric heat of water vapor sorption. The pore specific surface area of coal is not the determining parameter that controls water vapor sorption at least during the primary adsorption stage. Oxygen containing degree dominates the primary adsorption, and togethering with the cumulative pore volume determine the secondary adsorption. Higher temperature has limited effects on primary adsorption process. The isosteric heat of water adsorption decreases as water vapor uptake increases, which was found to be close to the latent heat of bulk water condensation at higher relative humidity. The results confirmed that the primary adsorption is controlled by the stronger bonding energy while the interaction energy between water molecules during secondary adsorption stage is relatively weak. However, the thermodynamics of coal-water interactions are complicated since internal bonding interactions within the coal are disrupted at the same time as new bonding interactions take place with the water molecules. Coal has a shrinkage/swelling colloidal structure with moisture loss/gain and it exhibits collapse behavior with some collapses irreversible as a function of relative humidity, which plays a significant role in determining moisture retention.

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Water Vapor Sorption and Diffusivity in Bio-Based Poly(ethylene vanillate)—PEV

Polymers ◽

10.3390/polym13040524 ◽

2021 ◽

Vol 13 (4) ◽

pp. 524

Author(s):

Greta Giacobazzi ◽

Claudio Gioia ◽

Micaela Vannini ◽

Paola Marchese ◽

Valérie Guillard ◽

...

Keyword(s):

Water Vapor ◽

Relative Humidity ◽

Sorption Isotherms ◽

Sorption Process ◽

Water Vapor Sorption ◽

Gravimetric Analysis ◽

Vapor Sorption ◽

Wide Range ◽

Poly Ethylene ◽

Segmental Flexibility

The dynamic and equilibrium water vapor sorption properties of amorphous and highly crystalline poly(ethylene vanillate) (PEV) films were determined via gravimetric analysis, at 20 °C, over a wide range of relative humidity (0–95% RH). At low RH%, the dynamic of the sorption process obeys Fick’s law while at higher relative humidity it is characterized by a drift ascribable to non-Fickian relaxations. The non-Fickian relaxations, which are responsible for the incorporation of additional water, are correlated with the upturn of the sorption isotherms and simultaneously the hysteresis recorded between sorption and desorption cycles. The sorption isotherms of amorphous and highly crystalline PEV are arranged in the same concentration range of that of PET proving the similarity of the two polyesters. Water diffusion coefficients, whose determination from individual kinetic sorption/desorption curves required treatment with the Barens–Hopfenberg model, were demonstrated to be ≈10× higher for amorphous PEV compared to amorphous PET. Such a difference originates from the enhanced segmental flexibility of PEV chains.

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