From the last post, SoilMoist is a soil conditioning polymer that improves the water retention of soil. When exposed to water, SoilMoist swells into a gel-like substance.
The Chemical composition of SoilMoist is cross-linked polyacrylamide
^Chemical structure of poly acrylamide.
Cross-linked polyacrylamide is highly hydrophilic, it can H-bond with water, which explains it’s usefulness as a water retention agent in soil.
Concerns have been raised that polyacrylamide used in agriculture may contaminate food with acrylamide, a known neurotoxin. While polyacrylamide itself is relatively non-toxic, it is known that commercially available polyacrylamide contains minute residual amounts of acrylamide remaining from its production, usually less than 0.05% w/w.
Information found on Wikipedia: http://en.wikipedia.org/wiki/Polyacrylamide