Swelling Behaviors and Water States of Fibrous Membranes Electrospun from PHBV-g-PVP

2012 ◽  
Vol 482-484 ◽  
pp. 1478-1482
Author(s):  
Wei Wang ◽  
Jian Da Cao ◽  
Ping Lan
Keyword(s):  
Water Absorption ◽  
Fiber Diameter ◽  
Bound Water ◽  
Free Water ◽  
Great Capacity ◽  
Electrospun Membranes ◽  
Dsc Characterization ◽  
Fibrous Membranes ◽  
Water Swelling ◽  
Swelling Behaviors

Fibrous membranes with a fiber diameter between 320 and 460 nm were electrospun from poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-graft-poly(N-vinylpyrrolidone) (PHBV-g-PVP) and their specific water absorption behaviors were investigated for biomaterial purposes. Water swelling experiments indicate that all samples have a great capacity for water uptake, while a remarkable overshoot occurs for the membranes electrospun from PHBV-g-PVP other than those from PHBV. DSC characterization indicates that only non-freezable bound water and free water can be distinguished in all electrospun membranes.

Preparation and Properties of a Water-Swelling Rubber by in situ Formed Lithium Acrylate in Nitrile Rubber

2005 ◽  
Vol 13 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Wentan Ren ◽  
Zonglin Peng ◽  
Yong Zhang ◽  
Yinxi Zhang
Keyword(s):  
Mechanical Properties ◽  
Bound Water ◽  
Free Water ◽  
High Water ◽  
Nitrile Rubber ◽  
Molar Ratio ◽  
Scanning Calorimetry ◽  
Swelling Properties ◽  
Water Swelling

Lithium acrylate (LiAA) was in situ prepared in nitrile rubber (NBR) through neutralization of lithium hydroxide (LiOH) and acrylic acid (AA) during mixing. The NBR/LiAA compounds were vulcanized with dicumyl peroxide (DCP). The in situ preparation and polymerization of LiAA were characterized using Fourier transform infrared (FTIR) spectrometer. The micrographs of the compounds and vulcanizates were explored using a scanning electron microscope (SEM). The effects of DCP and LiAA contents on the water-swelling and mechanical properties of the vulcanizates were studied. The relationship between the LiOH/AA molar ratio and the properties of the vulcanizates was investigated. The results showed that the in situ formed LiAA could improve the mechanical properties and water–swelling properties of the NBR/LiAA vulcanizates. The vulcanizates properly compounded had high water-swelling ratio over 800% and tensile strength more than 12MPa. The differential scanning calorimetry (DSC) measurements indicated that the water absorbed in the vulcanizate existed in PLiAA and NBR networks in three different physical states, namely, free water, freezable bound water and non-freezable bound water.

scholarly journals Effect of Heat Treatment on Water Absorption of Chinese fir Using TD-NMR

2018 ◽  
Vol 9 (1) ◽  
pp. 78 ◽  
Author(s):  
Yulei Gao ◽  
Kang Xu ◽  
Hui Peng ◽  
Jiali Jiang ◽  
Rongjun Zhao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Water Absorption ◽  
Bound Water ◽  
Treated Wood ◽  
Free Water ◽  
Scientific Basis ◽  
Transport Processes ◽  
Chinese Fir ◽  
Frequency Coding ◽  
Heat Treated

Knowledge of the dynamic changes in the water absorption process of heat-treated wood is important for providing a scientific basis for the reasonable application of heat-treated wood, especially for outdoor applications. Nuclear magnetic resonance (NMR) techniques provide detailed information about the moisture components and moisture transport processes in wood, which are not available with other methods. In this work, water absorption of untreated and heat treated Chinese fir (Cunninghamia lanceolata [Lamb.] Hook.) heartwood was investigated using various NMR methods. The heat treatment temperatures were varied between 160 °C and 220 °C. According to the spin-spin relaxation time (T2), there were two components of water in the samples heat-treated at 160 °C and 180 °C as well as the untreated sample, while three components of water were found in the samples heat-treated at 200 °C and 220 °C, and the mass of each component was calculated by the integral peak areas of the T2 curve. The amount of bound water and free water in heat-treated samples were less compared to the untreated ones, and the water absorption decreased correspondingly, due to the increasing heat-treated temperature. The results obtained by one dimensional frequency coding indicated that the heat treatment made wood difficult to be accessed by moisture. Besides, NMR images revealed that the free water absorption in latewood was faster than in earlywood, but earlywood could absorb more water than latewood.

scholarly journals Electrospun Membranes Based on Polycaprolactone, Nano-Hydroxyapatite and Metronidazole

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 931
Author(s):  
Ioana-Codruţa Mirică ◽  
Gabriel Furtos ◽  
Ondine Lucaciu ◽  
Petru Pascuta ◽  
Mihaela Vlassa ◽  
...  
Keyword(s):  
Fiber Diameter ◽  
Maximum Load ◽  
Guided Bone Regeneration ◽  
Attenuated Total Reflectance ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Total Reflectance ◽  
X Ray ◽  
Electrospun Membranes

The aim of this research was to develop new electrospun membranes (EMs) based on polycaprolactone (PCL) with or without metronidazole (MET)/nano-hydroxyapatite (nHAP) content. New nHAP with a mean diameter of 34 nm in length was synthesized. X-ray diffraction (XRD) and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) were used for structural characterization of precursors and EMs. The highest mechanical properties (the force at maximum load, Young’s modulus and tensile strength) were found for the PCL membranes, and these properties decreased for the other samples in the following order: 95% PCL + 5% nHAP > 80% PCL + 20% MET > 75% PCL + 5% nHAP + 20% MET. The stiffness increased with the addition of 5 wt.% nHAP. The SEM images of EMs showed randomly oriented bead-free fibers that generated a porous structure with interconnected macropores. The fiber diameter showed values between 2 and 16 µm. The fiber diameter increased with the addition of nHAP filler and decreased when MET was added. New EMs with nHAP and MET could be promising materials for guided bone regeneration or tissue engineering.

The Effect of Inner Layer Fiber Diameter and Fabric Structure on Transplanar Water Absorption and Transfer of Double-layered Knitted Fabrics

2021 ◽  
Vol 22 (2) ◽  
pp. 578-586
Author(s):  
Bahareh Yousefi ◽  
S. Mohammad Hosseini Varkiani ◽  
Siamak Saharkhiz ◽  
Zahra Khorram Toussi
Keyword(s):  
Water Absorption ◽  
Fiber Diameter ◽  
Knitted Fabrics ◽  
Fabric Structure ◽  
Layer Fiber

Determine the Moisture Distribution in Sewage Sludge by Drying Differential

2014 ◽  
Vol 665 ◽  
pp. 404-407 ◽  
Author(s):  
Wan Yu ◽  
Pei Sheng Li
Keyword(s):  
Sewage Sludge ◽  
Interstitial Water ◽  
Bound Water ◽  
Free Water ◽  
High Accuracy ◽  
Moisture Distribution ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Hot Air ◽  
Critical Water Content

Moisture distribution in sewage sludge was considered as the essential of thermal drying. Some methods were given in literatures to test the moisture distribution, but there was no standard method to determine the critical water content between different kinds of water. The municipal sewage sludge was dried by hot air in this work. Based on the drying curve, the derivative of drying rate with respect to dry basis moisture content was brought out to analyze the moisture distribution in sewage sludge. Results show that this method can easily determine the free water, interstitial water, surface water and bound water with a high accuracy. The present work can provide new insight to determine the moisture distribution in sewage sludge, which was still lacking in the literatures.

scholarly journals Testing the effects of basic numerical implementations of water migration on models of subduction dynamics

Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 537-555 ◽  
Author(s):  
M. E. T. Quinquis ◽  
S. J. H. Buiter
Keyword(s):  
Upper Mantle ◽  
Water Distribution ◽  
Mantle Wedge ◽  
Bound Water ◽  
Free Water ◽  
Water Velocity ◽  
Water Migration ◽  
Creep Flow ◽  
Dehydration Reactions ◽  
Slab Dehydration

Abstract. Subduction of oceanic lithosphere brings water into the Earth's upper mantle. Previous numerical studies have shown how slab dehydration and mantle hydration can impact the dynamics of a subduction system by allowing a more vigorous mantle flow and promoting localisation of deformation in the lithosphere and mantle. The depths at which dehydration reactions occur in the hydrated portions of the slab are well constrained in these models by thermodynamic calculations. However, computational models use different numerical schemes to simulate the migration of free water. We aim to show the influence of the numerical scheme of free water migration on the dynamics of the upper mantle and more specifically the mantle wedge. We investigate the following three simple migration schemes with a finite-element model: (1) element-wise vertical migration of free water, occurring independent of the flow of the solid phase; (2) an imposed vertical free water velocity; and (3) a Darcy velocity, where the free water velocity is a function of the pressure gradient caused by the difference in density between water and the surrounding rocks. In addition, the flow of the solid material field also moves the free water in the imposed vertical velocity and Darcy schemes. We first test the influence of the water migration scheme using a simple model that simulates the sinking of a cold, hydrated cylinder into a dry, warm mantle. We find that the free water migration scheme has only a limited impact on the water distribution after 1 Myr in these models. We next investigate slab dehydration and mantle hydration with a thermomechanical subduction model that includes brittle behaviour and viscous water-dependent creep flow laws. Our models demonstrate that the bound water distribution is not greatly influenced by the water migration scheme whereas the free water distribution is. We find that a bound water-dependent creep flow law results in a broader area of hydration in the mantle wedge, which feeds back to the dynamics of the system by the associated weakening. This finding underlines the importance of using dynamic time evolution models to investigate the effects of (de)hydration. We also show that hydrated material can be transported down to the base of the upper mantle at 670 km. Although (de)hydration processes influence subduction dynamics, we find that the exact numerical implementation of free water migration is not important in the basic schemes we investigated. A simple implementation of water migration could be sufficient for a first-order impression of the effects of water for studies that focus on large-scale features of subduction dynamics.

Characterization of thin water layers in pulp by tritium exchange. Part 1: Methods development

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Frances L. Walsh ◽  
Sujit Banerjee
Keyword(s):  
Water Content ◽  
Surface Area ◽  
Tritiated Water ◽  
Bound Water ◽  
Free Water ◽  
Fiber Surface ◽  
Bulk Water ◽  
Methods Development ◽  
A Value ◽  
A New Technique

Abstract A new technique for measuring the monolayer water content of fiber is presented. Tritiated water is added to a pulp/water suspension, whereupon the tritium partitions between the bulk water and the pulp. In the pulp phase the tritium can exchange with free water, bound water, and with hydroxyl and other protons present in the pulp matrix. The free water in the pulp is then removed by displacement with acetone. The tritium remaining in the pulp is mostly associated with tightly bound water, with a small fraction being tied up with the exchangeable hydrogen in pulp. The procedure provides a value of 10% for the tightly bound water content of hardwood or softwood fiber, either bleached or unbleached. If this water is assumed to cover the fiber surface as a monolayer, then an estimate of the wet surface area of the fiber can be obtained. This estimate compares well with independent measurements of surface area.

scholarly journals Water Adsorption to Leaves of Tall Cryptomeria japonica Tree Analyzed by Infrared Spectroscopy under Relative Humidity Control

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1107
Author(s):  
Wakana A. Azuma ◽  
Satoru Nakashima ◽  
Eri Yamakita ◽  
Tamihisa Ohta
Keyword(s):  
Hydrogen Bonding ◽  
Relative Humidity ◽  
Cryptomeria Japonica ◽  
Water Adsorption ◽  
Bound Water ◽  
Free Water ◽  
High Water ◽  
Water Molecules ◽  
Cross Sectional ◽  
Tissue Properties

Leaf water storage is a complex interaction between live tissue properties (anatomy and physiology) and physicochemical properties of biomolecules and water. How leaves adsorb water molecules based on interactions between biomolecules and water, including hydrogen bonding, challenges our understanding of hydraulic acclimation in tall trees where leaves are exposed to more water stress. Here, we used infrared (IR) microspectroscopy with changing relative humidity (RH) on leaves of tall Cryptomeria japonica trees. OH band areas correlating with water content were larger for treetop (52 m) than for lower-crown (19 m) leaves, regardless of relative humidity (RH). This high water adsorption in treetop leaves was not explained by polysaccharides such as Ca-bridged pectin, but could be attributed to the greater cross-sectional area of the transfusion tissue. In both treetop and lower-crown leaves, the band areas of long (free water: around 3550 cm−1) and short (bound water: around 3200 cm−1) hydrogen bonding OH components showed similar increases with increasing RH, while the band area of free water was larger at the treetop leaves regardless of RH. Free water molecules with longer H bonds were considered to be adsorbed loosely to hydrophobic CH surfaces of polysaccharides in the leaf-cross sections.

scholarly journals Effect of ageing on technological properties of goose meat

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Tomasz Żmijewski ◽  
Janusz Fryderyk Pomianowski ◽  
Katarzyna Tkacz
Keyword(s):  
Water Absorption ◽  
Shear Force ◽  
Ageing Time ◽  
Free Water ◽  
Storage Period ◽  
Raw Material ◽  
Water Volume ◽  
Technological Properties ◽  
Hydration Properties ◽  
Mean Values

AbstractAmong the poultry species, goose meat is relatively hard and cohesive and characterised by the highest chewiness and gumminess. Therefore, it can be assumed that goose meat ageing can improve its quality(1,2).The aim of the study was to determine the effect of ageing time of goose breast muscle on selected technological properties.The study material consisted musclus pectoralis of Polish White Kołuda oat geese, slaughtered at 15–17 weeks of age, weighing 6–7 kg. After slaughter, carcasses were cooled and breast muscles were cut out, vacuum packed and stored at 4°C ± 1°C. Analyses were performed 1, 7, 14, 21 days post mortem on eight breast muscles on each of the days (n = 8).The following parameters were determined: pH, muscle surface and cross-section colour, natural drip, free water, water absorption, thermal drip and shear force. A one-factor variance analysis method with Duncan's test (P ≤ 0.05) was used to evaluate the variation of mean values.It was demonstrated that muscle pH increases with an increase in the cool storage period. This parameter considerably increased from day 14 of ageing. Muscle colour changes were observed only on its surface between day 1 and 21. The ageing period had an effect on the meat hydration properties. Natural drip volume increased with an increase in the storage period and corresponded with the free water volume. A significantly greater volume of natural drip (1.77%) and a lower volume of free water (8.98%) were observed on day 21. Water absorption significantly increased on day 7 of ageing and remained constant until the end of the ageing time. A similar relationship was found while evaluating the shear force. A rapid drop in shear force was observed, which reflected an increase in meat tenderness by almost 5N between day 1 and 7 of the experiment. Based on the results, it can be concluded that the analysed raw material featured the most favourable technological properties on day 7 of ageing and that an extension of the ageing process was unjustified.

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