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Copyright (c) 2006-2014 MindTouch Inc.
This file and accompanying files are licensed under the MindTouch Master Subscription Agreement (MSA).
At any time, you shall not, directly or indirectly: (i) sublicense, resell, rent, lease, distribute, market, commercialize or otherwise transfer rights or usage to: (a) the Software, (b) any modified version or derivative work of the Software created by you or for you, or (c) MindTouch Open Source (which includes all non-supported versions of MindTouch-developed software), for any purpose including timesharing or service bureau purposes; (ii) remove or alter any copyright, trademark or proprietary notice in the Software; (iii) transfer, use or export the Software in violation of any applicable laws or regulations of any government or governmental agency; (iv) use or run on any of your hardware, or have deployed for use, any production version of MindTouch Open Source; (v) use any of the Support Services, Error corrections, Updates or Upgrades, for the MindTouch Open Source software or for any Server for which Support Services are not then purchased as provided hereunder; or (vi) reverse engineer, decompile or modify any encrypted or encoded portion of the Software.
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Ionic strength's effect on the ability of superabsorbent polymers to absorb liquids
|Sodium polyacrylate is added to beakers containing: |
NaCl is added to the first beaker.
The polymer absorbs all of the distilled water, most of the tap water, and some of the NaCl solution. If NaCl is added to the first beaker's resulting gel, water leaves the polymer network.
Sodium polyacrylate is made by polymerizing a mixture of of sodium acrylate and acrylic acid. The difference between the Na+ ion concentration inside the polymer network and the solution in which it is immersed generates an osmotic pressure that is alleviated as water diffuses into the polymer. As expected, the amount of liquid that can be absorbed depends on the ionic strength of the solution. This polymer can absorb 800 times its own weight of distilled water, 300 times its own weight in tap water, but only 60 times its own weight in urine (~0.9% NaCl).
An NSF funded Project