Role of filler and its heterostructure on moisture sorption mechanisms in polyimide films

AbstractThe moisture-induced shape memory effect (SME) is one of the most intriguing phenomena of wood, where wood can stably retain a certain deformed shape and, upon moisture sorption, can recover the original shape. Despite the long history of wood utilization, the SME is still not fully understood. Combining molecular dynamics (MD) and finite-element (FE) modeling, a possible mechanism of the SME of wood cell walls is explored, emphasizing the role of interface mechanics, a factor previously overlooked. Interface mechanics extracted from molecular simulations are implemented in different mechanical models solved by FEs, representing three configurations encountered in wood cell walls. These models incorporate moisture-dependent elastic moduli of the matrix and moisture-dependent behavior of the interface. One configuration, denoted as a mechanical hotspot with a fiber–fiber interface, is found to particularly strengthen the SME. Systematic parametric studies reveal that interface mechanics could be the source of shape memory. Notably, upon wetting, the interface is weak and soft, and the material can be easily deformed. Upon drying, the interface becomes strong and stiff, and composite deformation can be locked. When the interface is wetted again and weakened, the previously locked deformation cannot be sustained, and recovery occurs. The elastic energy and topological information stored in the cellulose fiber network is the driving force of the recovery process. This work proposes an interface behaving as a moisture-induced molecular switch.

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Factors effecting water-vapor transport through fibers (a brief review)

Theoretical and Applied Mechanics ◽

10.2298/tam0304277h ◽

2003 ◽

pp. 277-310 ◽

Cited By ~ 11

Author(s):

A.K. Haghi

Keyword(s):

Water Vapor ◽

Process Control ◽

Moisture Sorption ◽

Vapor Transport ◽

Water Vapor Transport ◽

Drying Behavior ◽

Control Devices ◽

Sorption Mechanisms ◽

Mathematical Relations ◽

Rela Tions

This review is a brief account of R& D results generated from drying behavior of carpets. First of all, the mathematical rela?tions are reviewed and then, they are developed in detail, which may be used to describe the moisture sorption mechanisms of car?pet. The effect of important parameters during the drying pro?cess are discussed and the mathematical relations are formulated to illustrate the range of their applications. However, challenges remain to be overcome through innovations, R& D investigations and advanced engineering, especially in designing process control devices.

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A Systematic Comparison of the Intrinsic Properties of Wheat and Oat Bran Fractions and Their Effects on Dough and Bread Properties: Elucidation of Chemical Mechanisms, Water Binding, and Steric Hindrance

Foods ◽

10.3390/foods10102311 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2311

Author(s):

Stefano Renzetti ◽

Mira Theunissen ◽

Karlijn Horrevorts

Keyword(s):

Steric Hindrance ◽

Binding Capacity ◽

Moisture Sorption ◽

Insoluble Fraction ◽

Glass Beads ◽

Water Binding ◽

Chemical Mechanisms ◽

Oat Bran ◽

Bread Properties

This study aimed at elucidating the contribution of chemical interactions, water binding, and steric hindrance on the effect of wheat and oat brans and of their fractions, i.e., soluble and insoluble, on dough and bread properties. For such purpose, an inert filler, i.e., glass beads of comparable particle size and with no water binding capacity and moisture sorption properties, was also studied. The glass beads provided breads most similar to the control, indicating the limited role of steric hindrance. Brans and bran fractions showed distinct compositional and physical properties. The soluble fraction from oat bran, rich in β-glucan, was less hygroscopic than the wheat counterpart and could bind more water, resulting in larger detrimental effects on bread quality. The β-glucan content showed a prevalent role in affecting gluten development, the thermo-setting behaviour of the dough, and crumb texture, i.e., cohesiveness and resilience. Overall, the comparison between the two brans and their fractions indicated that the interplay between water binding, mainly provided by the insoluble fraction, and the plasticizing properties of the soluble bran fraction controlled the effects on bread volume and texture. From a compositional standpoint, β-glucan content was a determining factor that discriminated the effects of wheat and oat brans.

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Role of surface molecular environment and amorphous content in moisture sorption behavior of milled Terbutaline Sulphate

European Journal of Pharmaceutical Sciences ◽

10.1016/j.ejps.2021.105782 ◽

2021 ◽

pp. 105782

Author(s):

Noor Ul Saba Bagwan ◽

Sneha Sheokand ◽

Amanpreet Kaur ◽

Gurudutt Dubey ◽

Vibha Puri ◽

...

Keyword(s):

Moisture Sorption ◽

Sorption Behavior ◽

Amorphous Content ◽

Terbutaline Sulphate

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Effects of non-solvents and electrolytes on the formation and properties of cellulose I filaments

Scientific Reports ◽

10.1038/s41598-019-53215-0 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 8

Author(s):

Ling Wang ◽

Meri J. Lundahl ◽

Luiz G. Greca ◽

Anastassios C. Papageorgiou ◽

Maryam Borghei ◽

...

Keyword(s):

Critical Role ◽

Cellulose Nanofibrils ◽

Moisture Sorption ◽

Electrolyte Solutions ◽

Thermomechanical Properties ◽

Wet Spinning ◽

Dynamic Vapor Sorption ◽

Drying Time ◽

And Performance

Abstract Coagulation is a critical process in the assembly of cellulose nanofibrils into filaments by wet spinning; however, so far, the role of the coagulation solvent has not been systematically elucidated in this context. This work considers organic non-solvents (ethanol, acetone) and aqueous electrolyte solutions (NaCl(aq), HCl(aq), CaCl2(aq)) for the coagulation of negatively charged cellulose nanofibrils via wet spinning. The associated mechanisms of coagulation with such non-solvents resulted in different spinnability, coagulation and drying time. The properties of the achieved filaments varied depending strongly on the coagulant used: filaments obtained from electrolytes (using Ca2+ and H+ as counterions) demonstrated better water/moisture stability and thermomechanical properties. In contrast, the filaments formed from organic non-solvents (with Na+ as counterions) showed high moisture sorption and low hornification when subjected to cycles of high and low humidity (dynamic vapor sorption experiments) and swelled extensively upon immersion in water. Our observations highlight the critical role of counter-ions and non-solvents in filament formation and performance. Some of the fundamental aspects are further revealed by using quartz crystal microgravimetry with model films of nanocelluloses subjected to the respective solvent exchange.

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Soil Nitrogen Sorption Using Charcoal and Wood Ash

Agronomy ◽

10.3390/agronomy11091801 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1801

Author(s):

Nur Hidayah Hamidi ◽

Osumanu Haruna Ahmed ◽

Latifah Omar ◽

Huck Ywih Ch’ng

Keyword(s):

Raw Materials ◽

Soil Amendments ◽

Theory Development ◽

Nutrient Deficiency ◽

Acid Soils ◽

Crop Productivity ◽

Wood Ash ◽

N Availability ◽

Sorption Mechanisms

This paper reviews the use of charcoal and wood ash in acid soils as adsorbents to improve N availability at the same time improving their soil fertility and crop productivity. Soil acidification poses a major challenge in agricultural sustainability and it is serious in highly weathered soils such as Ultisols and Oxisols which are noted for nutrient deficiency and Al and Fe ions toxicities. Understanding sorption mechanisms and isotherms is important for the improvement of soil N availability particularly inorganic N. However, understanding the sorption mechanisms in relation to charcoal and wood ash as absorbents in the literature is difficult because the soil amendments vary depending on their raw materials or sources of origin. Therefore, one of the objectives of this review is to provide recent research findings and theory development on the role of charcoal and wood ash in agriculture. Furthermore, this review focuses on how charcoal and wood ash improve N availability through physical, chemical and biological processes in mineral acidic soils. Balanced application and good understanding of the role of charcoal and wood ash as soil amendments have potential benefits to improve N availability and crop productivity.

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