Types of super absorbent polymer
There are two types of super absorbent polymer: potassium polyacrylate and sodium polyacrylate.
And there’re big differences between them:
| Raw materials | Price | Mainly Usages | |
|---|---|---|---|
| sodium polyacrylate | sodium hydroxide, acrylic acid, etc. | about USD 1,500/Ton | for the paper diapers, sanitary, etc. |
| potassium polyacrylate | potassium hydroxide, acrylic acid, etc. | about USD 3,000/Ton | for agriculture |
Potassium polyacrylate will absorb water and turn to water gel after rain or irrigate. And gel can release water to plant when soil is dry enough. After releasing, potassium polyacrylate gel will turn to powder/granule and waiting for the next rain.
The period of validity is about 3-10 years and potassium polyacrylate can be slowly decomposed into potassium ion, ammonia, water, carbon dioxide in the soil.
So potassium polyacrylate can help plants growing well and it’s mainly used in agriculture.
For now, potassium polyacrylate‘s price is about USD3000/ton.
Sodium polyacrylate’s price is about USD1500 / ton. (The price of inferior type can be lower than USD1000 / ton.)
As another type of super absorbent polymer, sodium polyacrylate is mainly used in producing absorption products such as paper diapers, sanitary towels.
Unlike potassium polyacrylate, sodium polyacrylate‘s water gel won’t release water to plants and break down in few days after mixing with soil.
This is meaning, sodium polyacrylate can’t help plants growing at all. Conversely, the sodium ion will let soil hardening.
So sodium polyacrylate should not be used in agriculture.
But sodium polyacrylate‘s price is much lower than potassium polyacrylate and it’s hard to distinguish between them, there’s some fake “potassium polyacrylate” that is sodium polyacrylate in the marketing.