The osmotic effect
Absorption depends on the concentration difference between the polymer network and the surrounding liquid. Dissolved salts in urine reduce that difference, so the network takes up less liquid than it would from fresh water.
How large the difference is
The drop varies with concentration, which itself varies with hydration and diet. In practice, capacity in urine is a fraction of the deionized water figure, so sizing from water data consistently under-delivers.
Choosing accordingly
Grades described as salt-tolerant retain a larger share of their capacity in saline liquid. They may show lower numbers in pure water, so compare candidates using the liquid that matters.
Testing approach
Use real urine or a recognised simulant for evaluation. Test at a realistic temperature, keep the sample source consistent, and run repeats because biological variation between samples is significant.
About FLORPOLY: FLORPOLY supplies super absorbent polymer for urine solidification in portable toilets, medical collection products and outdoor hygiene items, with grades selected for performance in saline liquids. Uptake speed, gel strength and particle size can be tailored. Contact FLORPOLY for a specification sheet, free sample or application advice.
Da maohua
Zhengzhou Flor New Materials Co., Ltd. specializes in SAP super‑absorbent polymer products. Serving personal hygiene, agriculture & horticulture, pet supplies and other industries, we leverage supply‑chain resources to provide particle‑size selection, performance matching and customized solutions based on clients’ practical requirements.
