Preparation and properties of waterborne polyurethane-urea/sodium alginate blends for high water vapor permeable coating materials

2007 ◽  
Vol 105 (3) ◽  
pp. 1168-1176 ◽  
Author(s):  
Jong-Kook Yun ◽  
Hye-Jin Yoo ◽  
Han-Do Kim
Keyword(s):  
Water Vapor ◽  
Sodium Alginate ◽  
Waterborne Polyurethane ◽  
High Water ◽  
Coating Materials

Sodium alginate–gelatin polyelectrolyte complex membranes with both high water vapor permeance and high permselectivity

2011 ◽  
Vol 375 (1-2) ◽  
pp. 304-312 ◽  
Author(s):  
Yifan Li ◽  
Huiping Jia ◽  
Qinglai Cheng ◽  
Fusheng Pan ◽  
Zhongyi Jiang
Keyword(s):  
Water Vapor ◽  
Sodium Alginate ◽  
Polyelectrolyte Complex ◽  
High Water

scholarly journals Water vapor transmission properties of acrylic organic coatings

2020 ◽  
Author(s):  
Réka Lilla Kovács ◽  
Lajos Daróczi ◽  
Péter Barkóczy ◽  
Eszter Baradács ◽  
Eszter Bakonyi ◽  
...  
Keyword(s):  
Water Vapor ◽  
Transmission Rate ◽  
Performance Testing ◽  
Preexponential Factor ◽  
Diffusion Activation Energy ◽  
Vapor Permeability ◽  
Coating Materials ◽  
Comparative Performance ◽  
Water Vapor Transmission ◽  
Arrhenius Function

AbstractIn this work, we evaluate the water vapor transmission rate (WVTR), the permeability (P), solubility (S), and diffusion (D) coefficients of Paraloid B44, Paraloid B72, and Incralac coatings in the temperature range of 5–35°C. The Arrhenius function—diffusion activation energy and preexponential factor—has also been determined from the data: $$D_{B44} = 35.2\;{\text{cm}}^{2} \;{\text{s}}^{ - 1} \exp \left( { - 25\;{\text{kJ mol}}^{ - 1} /{\text{RT}}} \right)$$ D B 44 = 35.2 cm 2 s - 1 exp - 25 kJ mol - 1 / RT ; $$D_{B72} = 9.5\;{\text{cm}}^{2} \;{\text{s}}^{ - 1} \exp \left( { - 23\;{\text{kJ mol}}^{ - 1} /{\text{RT}}} \right)$$ D B 72 = 9.5 cm 2 s - 1 exp - 23 kJ mol - 1 / RT ; $$D_{\text{Incralac}} = 622.8\;{\text{cm}}^{2} \;{\text{s}}^{ - 1} { \exp }\left( { - 28\;{\text{kJ mol}}^{ - 1} /{\text{RT}}} \right)$$ D Incralac = 622.8 cm 2 s - 1 exp - 28 kJ mol - 1 / RT . These resins are important coating materials, for example, for conservators to protect metallic artifacts, such as statues, against corrosion. Despite Paraloid B44 and B72 resins being considered as reference materials in conservation practice, that is, new coating materials (either water vapor retarders or transmitters) are often compared to them, there are no comprehensive data for the quantities describing the vapor permeability (P, S, D) of these materials. The measurements are based on the ISO cup-method using substrate/coating composite samples. The strength of this technique is that it can also be used when the coating is non-self-supporting; nevertheless, P, S, and D can be deduced for the coating layer itself, and it seems to be a standardizable procedure for comparative performance testing of coating materials. Paraloid B72 layers exhibited higher WVTRs—from 39 to 315 g m−2 day−1 as the temperature increased from 5 to 35°C—compared to Paraloid B44 and Incralac coatings—from 17 to 190 g m−2 day−1, respectively. The transmission rate parameters were also compared to the results of corrosion tests. Incralac was the most effective corrosion inhibitor, and the performance of the B44 was better than the B72, which is in good agreement with the transmission rate tests.

scholarly journals Torrefaction of Woody and Agricultural Biomass: Influence of the Presence of Water Vapor in the Gaseous Atmosphere

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 30
Author(s):  
María González Martínez ◽  
Estéban Hélias ◽  
Gilles Ratel ◽  
Sébastien Thiéry ◽  
Thierry Melkior
Keyword(s):  
Water Vapor ◽  
Water Content ◽  
Wheat Straw ◽  
Beech Wood ◽  
High Water ◽  
High Water Content ◽  
Biomass Degradation ◽  
Moist Atmosphere ◽  
Thermochemical Transformation ◽  
Degradation Reactions

Biomass preheating in torrefaction at an industrial scale is possible through a direct contact with the hot gases released. However, their high water-content implies introducing moisture (around 20% v/v) in the torrefaction atmosphere, which may impact biomass thermochemical transformation. In this work, this situation was investigated for wheat straw, beech wood and pine forest residue in torrefaction in two complementary experimental devices. Firstly, experiments in chemical regime carried out in a thermogravimetric analyzer (TGA) showed that biomass degradation started from lower temperatures and was faster under a moist atmosphere (20% v/v water content) for all biomass samples. This suggests that moisture might promote biomass components’ degradation reactions from lower temperatures than those observed under a dry atmosphere. Furthermore, biomass inorganic composition might play a role in the extent of biomass degradation in torrefaction in the presence of moisture. Secondly, torrefaction experiments on a lab-scale device made possible to assess the influence of temperature and residence time under dry and 100% moist atmosphere. In this case, the difference in solid mass loss between dry and moist torrefaction was only significant for wheat straw. Globally, an effect of water vapor on biomass transformation through torrefaction was observed (maximum 10%db), which appeared to be dependent on the biomass type and composition.

Polyurethane Electrospun Fiber Biomimetics Membrane for Constructing the Structure of Grain Layer with Good Breathability for Cattle Split Leather

2021 ◽  
Vol 116 (8) ◽  
Author(s):  
Nan Chen ◽  
Yanchun Li ◽  
Jianbo Qu ◽  
Jian-Yong Wang
Keyword(s):  
Water Vapor ◽  
Electrospun Fiber ◽  
Water Vapor Permeability ◽  
Waterborne Polyurethane ◽  
Vapor Permeability ◽  
High Porosity ◽  
Foam Layer ◽  
Fiber Morphology ◽  
Woven Structure ◽  
Superfine Fiber

The traditional thick coating on split leather does not have the ability to breathe like full grain leather.  The air and water vapor permeabilities of full grain leather are well known properties due to its fiber woven structure. Simulating the fiber morphology and weaving structure of the dermis or grain layer is very important to construct a top surface layer for split leather. In this paper, a PU (polyurethane) foam layer is put first on the split to enhance the adhesion of a second application of a superfine fibrous PU resin. This foam uses well-known waterborne polyurethane foaming technology. This dried foam has good breathability because of high porosity. A superfine fiber membrane is next put atop of the foam layer by using an electro-spun polyurethane resin. This second resin imitates collagen fibers in the network structure of the leathers’ grain layer. Thus, this resultant electrospun fiber biomimetics membrane simulated the grain layer of natural leather. SEM showed the morphology and structure of this electrospun fiber biomimetic membrane to be like that of the grain layer of natural leather. The porosity and apparent density were basically the same as the grain of leather, which were 63.65% and 583.878 kg/m3 respectively. The air and water vapor permeability of the biomimetics membrane were also as high as 2250 mL·cm-2·h-1 and 8753.02 μg·cm-2·h-1 respectively. Therefore, the biomimetics membrane largely restored the ability to breathe of split leather. Thus, this method simulates the performance and structure of full grain leather and is a novel method for industrial production

Degradation of Solid Oxide Fuel Cell Cathodes Accelerated at a High Water Vapor Concentration

2010 ◽  
Vol 7 (2) ◽  
Author(s):  
S. H. Kim ◽  
K. B. Shim ◽  
C. S. Kim ◽  
J. T. Chou ◽  
T. Oshima ◽  
...  
Keyword(s):  
Water Vapor ◽  
Voltage Drop ◽  
Cell Voltage ◽  
High Water ◽  
Solid Oxide ◽  
Constant Current ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Oxide Fuel ◽  
Constant Current Density

The influence of water vapor in air on power generation characteristic of solid oxide fuel cells was analyzed by measuring cell voltage at a constant current density, as a function of water vapor concentration at 800°C and 1000°C. Cell voltage change was negligible at 1000°C, while considerable voltage drop was observed at 800°C accelerated at high water vapor concentrations of 20 wt % and 40 wt %. It is considered that La2O3 formed on the (La0.8Sr0.2)0.98MnO3 surface, which is assumed to be the reason for a large voltage drop.

Fabrication of Poly(ε-caprolactone)-Based Biodegradable Packaging Materials with High Water Vapor Barrier Property

2020 ◽  
Vol 59 (51) ◽  
pp. 22163-22172
Author(s):  
Yitong Ding ◽  
Qian Zhou ◽  
Aichun Han ◽  
Hongxun Zhou ◽  
Rong Chen ◽  
...  
Keyword(s):  
Water Vapor ◽  
High Water ◽  
Barrier Property ◽  
Packaging Materials ◽  
Water Vapor Barrier ◽  
Biodegradable Packaging

scholarly journals Study on Waterproof and Air Permeability of Inorganic Insulated Decorative Panel

2018 ◽  
Vol 175 ◽  
pp. 01001
Author(s):  
Hu Xiang-lei ◽  
Wang Hong-jun ◽  
Gao Ying
Keyword(s):  
Water Vapor ◽  
Weak Link ◽  
Protective Layer ◽  
Outer Wall ◽  
High Water ◽  
Air Permeability ◽  
Composite Panel ◽  
Vapor Flux ◽  
System Supplier ◽  
Complete Set

According to the climatic characteristics, the paper investigates relation between waterproof and air permeability of inorganic insulated decorative panel. The paper believes there are two main problems in the waterproof of inorganic insulated decorative panel, one is the gap is a weak link for waterproof as some weather proofing silicone sealants have poor elastic modulus, the other is the failure of construction details causes partial waterproofing failure. The composite panel system is best supplied in a complete set by the system supplier, which is a main comprehensive solution to the waterproofing problem of the composite panel. Through analyzing software simulation and experimental construction, the paper puts forward suggestion that hot summer and cold winter areas should take practical technical measures, including the use of the protective layer with high water vapor flux density or the installation of exhaust plugs in the outer wall base, or setting water vapor escaping channel such as PVC exhaust plug in the glue seam, in the actual project.

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