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Superabsorbent polymer: Polymer that can absorb and retain extremely large amounts of a liquid relative to its own mass. [5] Notes: The liquid absorbed can be water or an organic liquid. The swelling ratio of a superabsorbent polymer can reach the order of 1000:1. Superabsorbent polymers for water are frequently polyelectrolytes.
The heat exchanger arrangement permits an absolute temperature difference (e.g. 0.27 °C/atm J–T cooling for air) to go beyond a single stage of cooling and can reach the low temperatures required to liquefy "fixed" gases. The Hampson–Linde cycle differs from the Siemens cycle only in the expansion step.
Air is liquefied by the Linde process, in which air is alternately compressed, cooled, and expanded, each expansion results in a considerable reduction in temperature. With the lower temperature the molecules move more slowly and occupy less space, so the air changes phase to become liquid.
In materials science, liquefaction [1] is a process that generates a liquid from a solid or a gas [2] or that generates a non-liquid phase which behaves in accordance with fluid dynamics. [3] It occurs both naturally and artificially. As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to ...
This super-absorbent polymer (SAP) has the ability to absorb 100 to 1000 times its mass in water. Sodium polyacrylate is an anionic polyelectrolyte [2] with negatively charged carboxylic groups in the main chain. It is a polymer made up of chains of acrylate compounds. It contains sodium, which gives it the ability to absorb large amounts of water.
The reaction results in a polymer which is also soluble in the chosen solvent. Heat released by the reaction is absorbed by the solvent, reducing the reaction rate. Moreover, the viscosity of the reaction mixture is reduced, preventing autoacceleration at high monomer concentrations. A decrease in viscosity of the reaction mixture by dilution ...
The liquid molecules are more attracted to other liquid molecules as compared to the polymer surface. Because the polymer surfaces are solid surfaces, surface tension cannot be measured in a traditional way such as using a Wilhelmy plate. Instead, contact angles can be used to indirectly estimate the surface tension of polymer surfaces. [3]
Exposing the polymer solution to a vapor of anti-solvent; Evaporating the solvent in atmospheric air or at high temperature; The rate at which phase inversion occurs and the characteristics of the resulting membrane are dependent on several factors, including: [2] Solubility of solvent in the anti-solvent; Insolubility of the polymer in the ...