Generally these are high purity, high viscosity pulps that are swollen in sodium hydroxide initially, followed by reaction with organic epoxides or chlorides like ethylene oxide or methyl chloride to form an organic polymer called cellulose ethers (methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, etc.). Cellulose ethers are used for thickening of fluids such as toothpaste, ketchup, shampoos, diet drinks and hundreds of other applications.