Permeability to liquids

The impermeability of solid Foraflon has been verified with respect to several liquid compounds. 1 

Mineral acids A 20 mm diameter Foraflon tube, 2 mm thick, has not allowed any trace of hydrochloric acid or sulfuric acid to pass through its walls during six months at 100°C. On the other hand, a certain permeability to hydrochloric acid is noted above 70°C. 

Other liquids Foraflon is not at all or only very slightly permeable to aliphatic and aromatic hydrocarbons, perchloroethylene, and trichloroethylene. 

Penetrant carbon dioxide nitrogen oxygen water vapor 

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Make a numerical estimate, with an explanation of the assumptions involved, of the specific surface area that would be found by (a) a rate of dissolving study, (b) Harkins and Jura, who find that at the adsorption of water vapor is 6.5 cm STP/g (and then proceed with a heat of immersion measurement), and (c) a measurement of the permeability to liquid flow through a compacted plug of the powder. 

Hence polyethylene will be more permeable to liquids of similar solubility parameter, e.g. hydrocarbons, than to liquids of different solubility parameter but of similar size. The permeabilities of a number of polymers to a number of gases are given the Table 5.77. ... 

Let the gas and liquid be contained in a cylinder of unit cross-section, fitted with pistons and fixed diaphragms as shown in Fig. 56. a is an impermeable piston, a fixed diaphragm permeable to gas but not to liquid (the upper surface of a nonvolatile liquid satisfies this condition), 7 is a piston permeable to liquid, but not to dissolved gas, and 8 is an impermeable diaphragm which can be put over or 7 as desired. 

Polymers are permeable to liquids having similar solubility parameters. Several different celts have been designed to measure the permeability of membranes to gases and vapors. 

The normal structure of the cell wall is broken by pits. Changes appear already in the growth period of the cell. For instance, early stages of pit formation in softwoods are visible in the primary wall just before the cell reaches its final dimensions (primary pit fields). The microfibril network is loosened and new microfibrils are oriented around these points. The structure in the middle of the circles is tightened and the radially oriented microfibril bundles finally form a netlike membrane, permeable to liquids (margo) (Fig. 1-17). The central, thickened portion of the pit membrane... 

Glazes for ceramic bodies and porcelain enamels for metallic substrates are coatings that are applied to these surfaces with a variety of purposes chemical inertness, zero permeability to liquids and gases, cleanability, smoothness and resistance to abrasion and scratching, mechanical strength, and decorative and aesthetic considerations [12]. 

Material that is transitional between snow and glacier ice. It is formed from snow after passing through one summer melt season and becomes glacier ice after its permeability to liquid water falls to zero, first detection... 

From that point of view it seems natural that special consideration should be given to the composite membranes in which one component consists of liquid crystal. The transitions from crystalline to mesophase state are connected with mobility increase thus influencing the transport properties of these composite systems. However, it was only recently that a discontinuous jump of permeability to liquids, gases and vapours in the vicinity of transition temperature of the liquid crystal phase has been discovered. Membranes of this type form a new class of composites which deserve special consideration due to their particular properties. 

Note L, longitudinal R, radial T, tangential S, sapwood H, heartwood 1, permeability to liquid g, permeability to gas a, air-dried sample o, oven-dried sample. 

POP s. See Persistent Organic Pollutants, porosity. An expression of the degree of permeability to liquids and large organic molecules in ion exchange resins. 

Aromatic amorphous or semicrystalline polyamides, PARA, such as copolyamide from caprolactam, hexamethylenediamine and iso- and tere-phthalic acids, PA-6IT6, or copolyphthalamide, PPA, are frequent components of polymer blends. Their advantage is low permeability to liquids and gases, stiffness and high HDT. Several blends of PP with PARA have been described, e.g. with either PP-MA, PE-MA, or PP grafted either with acrylic acid or GMA. Usually, these blends must be heat stabilized with phosphite ester or hydrazine. The alloys are often reinforced by addition of glass fibers and talc. 

The bulky nature of absorbent papers also makes them permeable to liquids. Based on this property, absorbent papers are used as filter media in coffee makers, in laboratory procedures for the recovery of crystalline solids, in fuel and oil filters for all types of machinery, in air filters for computer hard drives, and in many other similar applications. 

Osmosis is a process of diffusion driven by a chemical potential gradient. For example, if pure liquid is separated from a salt solution by a membrane that is permeable to liquid, but not to salt, pure liquid will diffuse into the salt-rich side. This type of transport occurs in general when liquid A and B are separated by a membrane permeable only to B. A dramatic example is shown in Fig. 1 Yoldas [2] prepared a sol of alumina in water, placed it into a bag made from a dialysis membrane, and immersed the bag in alcohol as the water diffused out of the sol into the alcohol bag, the sol contracted and finally gelled. Of course, it is not necessary to have a membrane to have... 

The gel solution contains 1,500 ppm xanthan biopolymer. Flow characteristics of this gel solution will be assumed to be the same as those for xanthan flowing in Berea sandstone. 26 Find the injection time and volume of gel solution injected when the polymer reaches a distance of 50 ft from the well in the high-permeability zone. It will be assumed that the high-permeability zone is at Sgr in the vicinity of the injection wellbore, while the low-permeability zone is at initial oil saturation until polymer injection begins. Relative permeability relationships for this reservoir rock are given by Eqs. 5.66 through 5.68. Base permeability for these relationships is the absolute permeability to liquid. 

Plastic Automotive Fuel Tanks. The North American auto industry is converting to plastic automotive fuel tanks from blow-molded HDPE. The advantages of HDPE tanks over the usual steel tanks are no corrosion, lighter than steel, easily shaped to fit in the car, and more puncture resistant than steel. However, the HDPE tanks suffer from high permeability to liquid gasoline. 

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