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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 ...
Liquid nitrogen. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The liquefaction of gases is a complicated process that uses various compressions and expansions to achieve high pressures and very low temperatures, using, for example, turboexpanders.
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]
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]
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.
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 ...
Complex fluids are mixtures that have a coexistence between two phases: solid–liquid (suspensions or solutions of macromolecules such as polymers), solid–gas , liquid–gas or liquid–liquid . They exhibit unusual mechanical responses to applied stress or strain due to the geometrical constraints that the phase coexistence imposes.
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 phase. Solid–solid phase changes are typically very slow and have a relatively low heat ...