Such polymeric materials are also commonly referred to as hydrocolloids", and can include polysaccharides such as carboxymethyl starch, carboxymethyl cellulose, and hydroxypropyl cellulose; nonionic types such as polyvinyl alcohol, and polyvinyl ethers; cationic types such as polyvinyl pyridine, polyvinyl inorpholinione, and N,Ndimethylaminoetilyl or N,N-diethylaminopropyl acrylates and methiacry