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+ Polymer characterization
+ Polymerization
+ Polymer physics
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Albert Joseph Hagemyer

What is swelling degree and how can one calculate this for polymer?

Ashish Panday  Follow

When a cross-linked polymer keep in a good solvent, it become swell rather than dissolve. Swelling degree define the change of dimension of polymer. A highly cross-linked polymer shows less degree of swelling.
The swelling value can be calculated by using the following formula:
Swelling (%) = (Ws - Wd)/Wd × 100
Where
Wd= Weight of polymer
Ws= weight of swollen polymer

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Nate Wyatt  Follow

This is depending on so many factors ; types of oligomers, catalyst, quring agents, Solvents,synthetic temperature and then physical steat of products mostly cross linked polymers two types small chain clp and big chain clp , small chain clp not shows swelling property they are dissolved directly . So if you want to study cross linkages of polymer use comparatively same pure non cross linking polymers make standard analysis reports physical and chemical and then same analysis do on clp thanks

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Brian White  Follow

All disscution is going well but first of all we should answer what for one wants to calculate swelling degree as it is the choice of medium (solvent). To estimate crosslinking or Molecular weight between the junctions-we should choose the proper solvent and I advice to check more solvents taking into account                          interaction between the chains and between the solvent. And here of course Flory theory and modification of it is very important. In the begining of sample analysis it is important to estimate the solubility of the sample in the studied solvent-do not forget about that.
But there are some studies which neeed to calculate the swelling degree for particular application. So it is much simpler. and here the advice of Omkar is good but do not forget as well in this case that part of your polymer can be solved-so check it after the drying of the sample after the swelling test. Otherwice you can missinterpret the results. Of course the temperature is very important and the way of weighting of the swollen sample. Must be very reproducible.
Helena

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Carlos Torres  Follow

The degree of swelling is usually calculated for hydrogels. That is, three-dimensional networks obtained from cross-links of one or more types of polymers. swelling is one of the basic characteristics of hydrogels, and basically, swelling measured to prove that a compound is hydrogel. Swelling means that the hydrogel does not dissolve in the solvent but swells. The stronger the cross-linked hydrogels, the lower the swelling ratio (because the porosity of such hydrogels will be lower and consequently the space will be lower for solvent adsorption) and vice versa. Whether the low swelling or high swelling hydrogel is good depends on the application of the hydrogel. In addition to the formula mentioned in the answers above, you can calculate the degree of swelling as a swelling ratio and with a simple formula Ws/Wd. The value obtained is in grams per gram. For example, if you get the value of 2, it means that the hydrogel in question absorbs 2 grams of solvent per gram of its weight (Without dissolves). In this article, we have discussed about hydrogel swelling and its importance in skin fillers, which may be useful for you: Article Temperature-dependent formulation of a hydrogel based on Hya...


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Brian Dean  Follow

Dear Abdelkader BOUAZIZ, thank you so much for your answer. Have a nice day

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Bill Bradow  Follow

Apply this general formula,
Swelling (%) = (Ws - Wd)/Wd × 100
[ Wd= Weight of polymer; Ws= weight of swollen polymer]

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David Hague  Follow

Hello everyone, how can we calculate the swollen volume of the polymer from swelling index ?

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Muhammad Zubair  Follow

Swelling is an usual phenomena of interaction of a Polymer with SOLVENT. Insertion of  such liquid within polymer matrix tend to swell it. This could be either reversible or irreversible. Many a times, some olymer have a tendencey to absorb moisture which tend to change the associted properties. the total moisture insertion is not always reversible. A certain fraction forms a part the polymer matrix. 
Simple way to calculate the % swelling is to consider the difference of weight of the polymer before and after. However, taking dry weight of polymer should be exact to obtained the % swelling.

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Bubba Bear Huntington  Follow

Dear Nurcan Aşçı, this means that the polymer matrix undergone shrinkage. This is may be due to bed solvation, and if it is a polyelectrolyte, charge neutalization has occured. This is common fact in proteins. Other possible reasons may also exist. My Regards

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Charles Wardrop  Follow

Hi,
What if this degree of swelling results are negative, what comment we can do?
Thanks

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Christian Acevedo  Follow

This is means that the polymer has no swelling but has shrinkage.

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