No, totally different from diapers, I think. I spent more time on the web site. Their stuff is starch and diapers are petroleum. Here's from their FAQ:

Q. Iâ??ve tried superabsorbents before, but couldnâ??t really tell a difference in my plants.

A. Zeba is totally new, and totally different from other products. Youâ??ve likely had experience with the many polyacrylamide formulations (PAMs) sold on the market. PAMs are supersabsorbents made with petroleum-type PAM formulations, the active ingredient used in disposable diapers. PAMs hold water tightly â?? a good thing for diapers, but a bad thing when your plant fights it for a drink, which explains why these formulations are less effective in growing plants.