For your second question, whether beans can grow in hydrated Sodium Polyacrylate, the answer is yes! Sodium Polyacrylate is used as a soil substitute for growing plants. Sodium Polyacrylate is an extremely absorbent chemical -- it can absorb large amounts of water, and this is why it is used in baby diapers. But honestly, you could probably grow beans in most substances that absorb a good amount of water, such as paper towels or crumpled newspaper. You can read more about experiments using Sodium Polyacrylate on this website (scroll down to where it says "Wet Diaper Science"):

I don't know the answer to your question about sprouting beans in hydrated Sodium Polyacrylate, but it sounds like an easy experiment to do at your house.I'm guessing you have hydrated Sodium Polyacrylate, or you wouldn't be asking the question. It would be a good idea to try sprouting the beans in wet cotton, too, to be sure the problem is the hydrated Sodium Polyacrylate and not the beans, if they don't sprout in hydrated Sodium Polyacrylate. Sprouting beans in wet cotton would be the Control experiment for sprouting beans in hydrated Sodium Polyacrylate.

Keep asking questions!
Best wishes,