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Water Uptake Behavior (water + uptake_behavior)

Distribution by Scientific Domains

Polymers and Materials Science	75%

Selected Abstracts

MODELING VARIETAL EFFECT ON THE WATER UPTAKE BEHAVIOR OF MILLED RICE (ORYZA SATIVA L.) DURING SOAKING

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 6 2007
B.K. YADAV
ABSTRACT Milled rice is soaked until saturation before cooking and other processing. The soaking behavior of the milled rice is affected by varietal factor as well as initial moisture content (M0) of the samples. In the present study, tests were performed for milled whole kernels of 10 rice varieties ranging from low to high amylose content (16,29% d.b.) with three initial moisture levels (approximately 8, 12 and 16% d.b.) for monitoring water uptake in rice kernels during soaking at room temperature (25 ± 1C), in relation to the varietal differences manifested by the physicochemical properties. The water uptake by milled rice kernels took place at a faster rate in the beginning and was followed by a diminishing rate finally leading to a saturated value during soaking. The water uptake of the kernels during soaking could be best expressed by a modified exponential relationship with R2 values ranging from 0.971 to 0.998 for all varieties. The slope of the fitted straight line between actual and estimated moisture contents of milled rice during soaking using a modified exponential relationship was about unity (0.998) with a high R2 value of 0.989 and a root mean square error of 1.2% d.b. The parameters of the fitted model were the function of the M0 and the physicochemical properties of the milled rice. Using developed relationship, the water uptake of the milled rice during soaking could be estimated from its M0 and the physicochemical properties within±10% of the actual values. PRACTICAL APPLICATIONS This information would be useful for the scientific world working on the soaking characteristics of various varieties of rice, mainly for the modeling of the soaking process. It could also be used as a tool in selecting the rice varieties to meet their desired water uptake properties in relation to their psychochemical properties by rice breeder scientists. [source]

Water uptake behavior of layered silicate/starch,polycaprolactone blend nanocomposites

POLYMER INTERNATIONAL, Issue 2 2008
C Javier Pérez
Abstract The water uptake behavior of biodegradable layered silicate/starch,polycaprolactone blend nanocomposites was evaluated. Three different commercial layered silicates (Cloisite Na+, Cloisite 30B and Cloisite 10A) were used as reinforcement nanofillers. Tests were carried out in two different environments: 60 and 90% relative humidity using glycerol solutions. The clay/starch,polycaprolactone blend nanocomposites were obtained by melt intercalation and characterized by gravimetric measurements and tensile tests. The intercalated structure (determined by wide-angle X-ray diffraction) showed a decrease in water absorption as a function of clay content probably due to the decrease of the mean free path of water molecules. The diffusion coefficient decreased with clay incorporation but a further increase in the clay content did not show an important effect on this parameter. Elongation at break increased with exposure showing matrix plasticization. Mechanical properties of the nanocomposites deteriorated after exposure whereas they remained almost constant in the case of the neat matrix. Copyright © 2007 Society of Chemical Industry [source]

Surface characterization of flax, hemp and cellulose fibers; Surface properties and the water uptake behavior

POLYMER COMPOSITES, Issue 5 2002
Alexander Bismarck
The surface characteristics of several natural fibers,flax, hemp and cellulose,were investigated using scanning electron microscopy, BET-surface area and zeta (,-) potential measurements. ,-Potential measurements using the streaming potential method were performed in order to study the water uptake behavior as well as the surface properties of several natural fibers. The influence of different flax-fiber separation methods and several modifications, like industrial purification, and such a treatment followed by alkaline purification as well as polypropylene grafting on the fiber surface morphology, surface area and time- and pH-depending ,-potentials were studied. The time-dependence of the ,-potential, measured in 1 mM KCl solution, offeres and alternative possibility to estimate the water uptake behavior for nearly all investigated natural fibers. The water uptake data derived from the ,-potential measurements (, = f(t)) were compared with data from conventional water adsorption studies for some chosen examples. [source]