Swelling capacity
{{Short description|Amount of a liquid that can be absorbed by a polymer}}
{{Use mdy dates|date=February 2024}}
The swelling capacity of a polymer is the amount of a liquid that can be absorbed by it. This test can done by two methods:
- Beaker test method{{Cite journal |last1=Anandan |first1=Dhivyaa |last2=Madhumathi |first2=G. |last3=Nambiraj |first3=N. Arunai |last4=Jaiswal |first4=Amit K. |date=June 15, 2019 |title=Gum based 3D composite scaffolds for bone tissue engineering applications |url=https://www.sciencedirect.com/science/article/pii/S0144861719302863 |journal=Carbohydrate Polymers |volume=214 |pages=62–70 |doi=10.1016/j.carbpol.2019.03.020 |pmid=30926008 |s2cid=88481556 |issn=0144-8617|url-access=subscription }}
- Tea bag test method{{Cite journal |last1=Zhong |first1=Peihua |last2=Wang |first2=Jun |last3=Wang |first3=Xiaoxian |last4=Liu |first4=Jiaping |last5=Li |first5=Zhen |last6=Zhou |first6=Yichuan |date=2020 |title=Comparison of Different Approaches for Testing Sorption by a Superabsorbent Polymer to Be Used in Cement-Based Materials |journal=Materials |language=en |volume=13 |issue=21 |pages=5015 |doi=10.3390/ma13215015 |doi-access=free |issn=1996-1944 |pmc=7664450 |pmid=33172166|bibcode=2020Mate...13.5015Z }}
Beaker test method
In this method
- 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.{{cite journal | url=https://doi.org/10.1016/j.mex.2023.102251 | doi=10.1016/j.mex.2023.102251 | title=A beaker method for determination of microplastic concentration by micro-Raman spectroscopy | date=2023 | last1=Yang | first1=Zijiang | last2=Arakawa | first2=Hisayuki | journal=MethodsX | volume=11 | pmid=37448948 | pmc=10336159 }}
Tea bag test method
- In this method, 0.1 g of SAP material is placed into a permeable bag, which is suspended over excess water in a beaker.
- Wait 20 min. and weigh the bag and then calculate the percentage of swelling through the following formula:
- : (w2-w1)/(w1) %
- : w1= weight of the polymer (Before swelling)
- : w2= weight of the polymer (After swelling)
- Note: Filter paper only for removing water.
Schroeder's paradox
{{Main|Schroeder's paradox}}
Some polymers exhibit larger experimentally measured swelling capacity when immersed in pure liquid compared to testing with saturated vapor. This phenomenon is known as the Schroeder's paradox.