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A superabsorbent polymer (SAP) (also called slush powder) is a water-absorbing hydrophilic homopolymers or copolymers [1] that can absorb and retain extremely large amounts of a liquid relative to its own mass. [2] Water-absorbing polymers, which are classified as hydrogels when mixed, [3] absorb aqueous solutions through hydrogen bonding with ...
As an example of the latter, a "major commercial application of liquefaction is the liquefaction of air to allow separation of the constituents, such as oxygen, nitrogen, and the noble gases." [4] Another is the conversion of solid coal into a liquid form usable as a substitute for liquid fuels. [5]
Super-absorbent polymers (SAP) similar to sodium polyacrylate were developed in the 1960s by the U.S. Department of Agriculture. [3] Before the development of these substances, the best water absorbing materials were cellulosic or fiber-based like tissue paper, sponge, cotton, or fluff pulp.
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.
A small amount of superabsorbent polymer material is taken (0.1g) and it is placed in the beaker. 100 ml of deionized water is poured into the beaker. After 20 min the swollen polymer was separated by using [filter paper] By weighing the polymer, one can find the swollen capacity of the SAP material. [3]
As a type of superabsorbent polymer for plants (Ag-SAP), potassium polyacrylate can increase moisture availability to plants. It mixes with soil to increase the soil’s capacity for holding water (with water gel form which stay in soil for months [2]) and making it available to plants. This improved soil readily releases moisture, along with ...
However, only solid→liquid and liquid→solid phase changes are practical for PCMs. Although liquid–gas transitions have a higher heat of transformation than solid–liquid transitions, liquid→gas phase changes are impractical for thermal storage because large volumes or high pressures are required to store the materials in their gas ...
Contact angle, the angle at which a liquid droplet meets at a solid surface, is another way to characterize polymer surfaces. Contact angle (θ) is a measure of the wetting ability of the liquid on a solid surface. [4] Generally, due to low surface energy, liquids will not wet polymer surfaces and the contact angle will be greater than 90°. [3]