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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.
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 ...
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.
Larger amounts are supplied in metal tanks similar to gas cylinders, designed so a needle can fit through the valve opening. A syringe, carefully dried and flushed of air with an inert gas, is used to extract the liquid from its container. When working with pyrophoric solids, researchers often employ a sealed glove box flushed with inert gas.
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.
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]
Another application of polymer solutions includes the manufacture of fibers by wet or dry spinning or plastic films. Disadvantages of solution polymerization are decrease of monomer and initiator concentration leading to reduction of reaction rate, lower volume utilization of reactor, additional cost of the process related to solvent recycling ...
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 phase.